{"id":5323,"date":"2026-10-05T12:09:31","date_gmt":"2026-10-05T04:09:31","guid":{"rendered":"https:\/\/ballvalves.tw\/?p=5323"},"modified":"2026-10-19T10:18:48","modified_gmt":"2026-10-19T02:18:48","slug":"cf8m-material","status":"publish","type":"post","link":"https:\/\/ballvalves.tw\/ru\/cf8m-material\/","title":{"rendered":"CF8M Material: How to Specify a CF8M Ball Valve on the Drawing, the RFQ and the Certificate"},"content":{"rendered":"<p class=\"wp-block-paragraph\">CF8M material is the ASTM casting grade for 316-type stainless steel: 18 to 21 percent chromium, 9 to 12 percent nickel, 2 to 3 percent molybdenum, with carbon held to 0.08 percent. To specify a CF8M ball valve, write that casting grade against the cast parts, then add the five things the grade does not cover: the stem, the pressure rating, the seat material with its temperature limit, the end connection with its thread standard, and the certificate you want delivered with the valves. The rest of this guide explains each line, so that the quotation, the material certificate and the marking on the valve body all agree with your order.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">It is written for buyers and engineers who have to put the material line on a drawing or a purchase order and then defend it at goods-in. We are YZNG TRONG, a stainless steel ball valve manufacturer in Taiwan, and our ball valve bodies, end caps and balls are investment cast in CF8 and CF8M. The point to keep in mind throughout: &#8220;CF8M&#8221; describes the castings, and the rest of the valve needs its own lines.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>\u041e\u0441\u043d\u043e\u0432\u043d\u044b\u0435 \u0432\u044b\u0432\u043e\u0434\u044b<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>CF8M is cast 316. It is defined in ASTM A351 for pressure-containing castings, and its UNS number is J92900. The M is molybdenum, the element that resists chloride pitting; CF8 is the grade without it, the cast form of 304.<\/li>\n\n\n<li>A certificate for a cast 316 body says CF8M, not 316. Put the casting grade on the drawing or the order and the goods-in mismatch disappears.<\/li>\n\n\n<li>CF8M names the alloy of the cast parts only. The stem is a separate wrought part (316 bar to ASTM A276 on our three-piece valves), and the pressure rating, the temperature limit and the thread standard are separate lines.<\/li>\n\n\n<li>Six lines specify the valve: casting grade, stem, seat and temperature, pressure rating, end connection, documents. A worked example is given below.<\/li>\n\n\n<li>Check the delivery with the material test report and the marking on the body, not with a magnet.<\/li>\n\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">What CF8M material is<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">CF8M is a cast austenitic stainless steel grade defined in <a href=\"https:\/\/store.astm.org\/a0351_a0351m-24e01.html\" target=\"_blank\" rel=\"noopener\">ASTM A351\/A351M<\/a>, the specification for austenitic steel castings used in pressure-containing parts such as valve bodies, flanges and fittings. The same grade appears in ASTM A743, which covers corrosion-resistant castings for general use. It is the cast version of the 316 family: chromium and nickel for general corrosion resistance, plus molybdenum for resistance to pitting in chloride-bearing media. Its UNS number is J92900.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The letters are a code. Cast stainless steels are named under the system of the Alloy Casting Institute, which ASTM adopted, and the Steel Founders&#8217; Society of America sets the convention out in its <a href=\"https:\/\/www.sfsa.org\/wp-content\/uploads\/2021\/10\/s2.pdf\" target=\"_blank\" rel=\"noopener\">summary of specifications for high-alloy castings<\/a>. The first letter C means the alloy is intended for corrosion-resistant service in aqueous environments; an H in that position would mean heat-resistant service. The second letter gives the nominal chromium-nickel type, with the letters running from A towards Z as nickel rises, and F is the 19 percent chromium, 9 percent nickel type. The number relates to the maximum carbon content, 0.08 percent here. A letter at the end marks an added alloying element, and M stands for molybdenum. Read together, CF8M is a corrosion-resistant 19Cr-9Ni casting alloy with 0.08 percent maximum carbon and molybdenum added.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">On a ball valve, CF8M describes the parts that are cast. On our three-piece valves that is the body, the two end caps and the ball. The stem is a different product form: ASTM A276 Type 316 bar, the wrought grade of the same alloy family, CNC machined. The seats, the stem seal, the bolts and the handle are separate materials again. So a valve described as &#8220;CF8M&#8221; is a valve whose pressure-containing castings are CF8M, and the rest of the bill of materials still has to be read.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">How to specify a CF8M ball valve: six lines<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The material code covers the castings. Five more lines cover the rest of the valve, and together the six fit in one drawing note or one RFQ line. The table gives each line, what to write and why it exists as a separate line.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Line<\/th><th>What to write<\/th><th>Why it is a separate line<\/th><\/tr><\/thead><tbody><tr><td>1. Casting grade<\/td><td>&#8220;Body, end caps and ball: CF8M (cast 316)&#8221;, plus, if your quality system requires it, the specification the certificate is to be written against (ASTM A351, JIS G 5121 SCS14A or EN 1.4408)<\/td><td>The certificate names the casting grade, so the order should too<\/td><\/tr><tr><td>2. Stem<\/td><td>&#8220;Stem: 316 bar, ASTM A276, blowout-proof&#8221;<\/td><td>The stem is wrought and machined from bar; it is not covered by the casting certificate<\/td><\/tr><tr><td>3. Seat and temperature<\/td><td>&#8220;Seat: PTFE; working temperature \u221220 \u00b0C to +180 \u00b0C (\u22124 \u00b0F to +356 \u00b0F)&#8221; (a fully encapsulated sanitary seat: +80 \u00b0C \/ +176 \u00b0F maximum; on a valve with a pneumatic actuator, the actuator&#8217;s \u221220 \u00b0C to +80 \u00b0C, \u22124 \u00b0F to +176 \u00b0F, limits the assembly)<\/td><td>The seat, or on a pneumatic valve the actuator, sets the temperature ceiling long before the alloy does<\/td><\/tr><tr><td>4. Pressure rating<\/td><td>&#8220;1000 WOG&#8221;, &#8220;2000 WOG&#8221;, or the flange class (Class 150 or 300, JIS 10K or 20K)<\/td><td>The alloy has no rating; the valve design has<\/td><\/tr><tr><td>5. End connection and thread standard<\/td><td>Thread standard (PT, NPT or PF), or the weld, clamp or flange end, with its standard<\/td><td>A valve threaded to one standard does not seal reliably on pipe threaded to another<\/td><\/tr><tr><td>6. Documents<\/td><td>&#8220;Material test report for the castings with the delivery&#8221;, and the certificate type if your quality system requires one<\/td><td>The report is the document that fixes the grade; how to check it, and the marking on the body, is covered below<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">The first two lines describe the material and the next three the duty; the last one is the evidence you will check at goods-in. With all six lines, plus size, port and the service conditions as in the example below, two quotations can be compared line by line.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Written out for a one-inch three-piece valve, it reads:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Qty 50, 1 in. three-piece ball valve, full port, threaded ends PT. Body, end caps and ball: CF8M (cast 316). Stem: 316 bar (ASTM A276), blowout-proof. Seat: PTFE. Rating: 1000 WOG. Service: compressed air at ambient temperature. Material test report for the castings to be supplied with the delivery.<\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Three notes on the example. First, &#8220;316 stainless steel&#8221; is fine in the description, as long as the casting grade line exists; the certificate will say CF8M and the inspector needs a line on the order that matches it. Second, if your piping is NPT, say NPT; a line that only says &#8220;threaded&#8221; leaves the thread standard to the supplier&#8217;s guess, and our guide to <a href=\"https:\/\/ballvalves.tw\/ru\/%d0%ba%d0%be%d0%bd%d1%86%d0%b5%d0%b2%d1%8b%d0%b5-%d1%81%d0%be%d0%b5%d0%b4%d0%b8%d0%bd%d0%b5%d0%bd%d0%b8%d1%8f-%d0%ba%d0%bb%d0%b0%d0%bf%d0%b0%d0%bd%d0%be%d0%b2\/\">\u043a\u043e\u043d\u0446\u0435\u0432\u044b\u0435 \u0441\u043e\u0435\u0434\u0438\u043d\u0435\u043d\u0438\u044f \u043a\u043b\u0430\u043f\u0430\u043d\u043e\u0432<\/a> explains what each option commits you to. Third, the example stops at the valve. Quantity breaks, packaging and commercial terms belong in the RFQ proper, which our guide to <a href=\"https:\/\/ballvalves.tw\/ru\/%d0%b7%d0%b0%d0%bf%d1%80%d0%be%d1%81-%d0%bd%d0%b0-%d0%bf%d1%80%d0%b5%d0%b4%d0%bb%d0%be%d0%b6%d0%b5%d0%bd%d0%b8%d0%b5-%d0%bf%d0%be-%d0%ba%d0%bb%d0%b0%d0%bf%d0%b0%d0%bd%d0%b0%d0%bc\/\">writing a valve RFQ<\/a> covers. The first five lines are also what to read on a supplier&#8217;s drawing, and checking the supplier itself is a separate exercise we set out for <a href=\"https:\/\/ballvalves.tw\/ru\/3-piece-ball-valve-manufacturer\/\">three-piece ball valve manufacturers<\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Why the certificate says CF8M when the order says 316<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Because 316 and CF8M are the same alloy in two product forms, and each form has its own specification. 316 is the wrought designation, supplied as plate, bar and pipe under specifications such as ASTM A276 for bar. CF8M is the cast designation. Casting specifications such as ASTM A351 and A743 name the cast form CF8M, so a certificate issued against a casting specification names the casting grade, and nothing has gone wrong.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The mismatch shows up at goods-in. The purchase order says &#8220;316 stainless steel ball valve&#8221;, which is the ordinary commercial description and is accurate. The certificate says CF8M. An inspector comparing the two raises a nonconformance, the valves sit in quarantine, and someone has to write an explanation that could have been a line on the order. The fix is to put the casting grade on the drawing or the order template once, after which the two documents read the same way.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">One real difference remains. The composition windows are not the same, as the composition table later in this guide shows, and the microstructure of a casting is not that of rolled plate. Cite the specification that matches the product form you are buying, and the certificate can be checked against the specification it was actually produced to.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Where CF8M sits in our ball valve range<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Many of our series are stocked in CF8M with CF8 made to order, but not all of them, and the exceptions are the ones that catch buyers out. The table gives the standard build by series, so the grade line can be written to match what is on the shelf or flagged as a made-to-order item from the start.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Series<\/th><th>Standard material<\/th><th>Also available<\/th><\/tr><\/thead><tbody><tr><td><a href=\"https:\/\/ballvalves.tw\/ru\/%d0%bf%d1%80%d0%be%d0%b4%d1%83%d0%ba%d1%82\/%d0%be%d0%b4%d0%bd%d0%be%d1%81%d0%b5%d0%b4%d0%b5%d0%bb%d1%8c%d0%bd%d1%8b%d0%b9-%d1%88%d0%b0%d1%80%d0%be%d0%b2%d0%be%d0%b9-%d0%ba%d1%80%d0%b0%d0%bd-1000-wog\/\">One-piece threaded ball valve (R-1B)<\/a><\/td><td>CF8M (316), in stock<\/td><td>CF8 (304), made to order<\/td><\/tr><tr><td><a href=\"https:\/\/ballvalves.tw\/ru\/%d0%bf%d1%80%d0%be%d0%b4%d1%83%d0%ba%d1%82\/%d1%88%d0%b0%d1%80%d0%be%d0%b2%d0%be%d0%b9-%d0%ba%d1%80%d0%b0%d0%bd-%d1%81-%d1%81%d0%b2%d0%b0%d1%80%d0%bd%d1%8b%d0%bc-%d0%ba%d0%be%d1%80%d0%bf%d1%83%d1%81%d0%be%d0%bc-%d0%b8%d0%b7-%d0%b4%d0%b2%d1%83\/\">Seal-welded two-piece ball valve (V-2B, V-2C)<\/a><\/td><td>CF8 (304) and CF8M (316), both in stock<\/td><td>Socket weld version made to order in either grade<\/td><\/tr><tr><td><a href=\"https:\/\/ballvalves.tw\/ru\/%d0%bf%d1%80%d0%be%d0%b4%d1%83%d0%ba%d1%82\/%d0%b4%d0%b2%d1%83%d1%85%d0%ba%d0%be%d0%bc%d0%bf%d0%be%d0%bd%d0%b5%d0%bd%d1%82%d0%bd%d1%8b%d0%b9-%d1%88%d0%b0%d1%80%d0%be%d0%b2%d0%be%d0%b9-%d0%ba%d1%80%d0%b0%d0%bd-fxm-1000-wog\/\">MxF two-piece ball valve (male x female threads)<\/a><\/td><td>CF8 (304), in stock<\/td><td>CF8M (316), made to order<\/td><\/tr><tr><td><a href=\"https:\/\/ballvalves.tw\/ru\/%d0%bf%d1%80%d0%be%d0%b4%d1%83%d0%ba%d1%82\/2-%d1%88%d1%82-%d1%88%d0%b0%d1%80%d0%be%d0%b2%d1%8b%d1%85-%d0%ba%d1%80%d0%b0%d0%bd%d0%be%d0%b2-%d0%b2%d1%8b%d1%81%d0%be%d0%ba%d0%be%d0%b3%d0%be-%d0%b4%d0%b0%d0%b2%d0%bb%d0%b5%d0%bd%d0%b8%d1%8f\/\">2000 WOG two-piece ball valve (V-2NF)<\/a><\/td><td>CF8M (316), in stock<\/td><td>CF8 (304), made to order<\/td><\/tr><tr><td><a href=\"https:\/\/ballvalves.tw\/ru\/%d0%bf%d1%80%d0%be%d0%b4%d1%83%d0%ba%d1%82\/3-%d1%88%d1%82-%d1%88%d0%b0%d1%80%d0%be%d0%b2%d1%8b%d1%85-%d0%ba%d1%80%d0%b0%d0%bd%d0%be%d0%b2-%d1%82%d0%b8%d0%bf%d1%8b-pt-bw-sw\/\">Three-piece ball valve, manual (V-3A)<\/a><\/td><td>CF8M (316), in stock<\/td><td>CF8 (304), made to order<\/td><\/tr><tr><td><a href=\"https:\/\/ballvalves.tw\/ru\/%d0%bf%d1%80%d0%be%d0%b4%d1%83%d0%ba%d1%82\/3-%d1%88%d1%82-%d0%bf%d0%bd%d0%b5%d0%b2%d0%bc%d0%b0%d1%82%d0%b8%d1%87%d0%b5%d1%81%d0%ba%d0%b8%d1%85-%d1%88%d0%b0%d1%80%d0%be%d0%b2%d1%8b%d1%85-%d0%ba%d1%80%d0%b0%d0%bd%d0%be%d0%b2\/\">Three-piece ball valve with pneumatic actuator (V-3AM)<\/a><\/td><td>CF8M (316), in stock<\/td><td>CF8 (304), made to order<\/td><\/tr><tr><td><a href=\"https:\/\/ballvalves.tw\/ru\/%d0%bf%d1%80%d0%be%d0%b4%d1%83%d0%ba%d1%82\/%d1%80%d1%83%d1%87%d0%bd%d0%be%d0%b9-3-%d1%85%d0%be%d0%b4%d0%be%d0%b2%d0%be%d0%b9-%d1%88%d0%b0%d1%80%d0%be%d0%b2%d0%be%d0%b9-%d0%ba%d1%80%d0%b0%d0%bd\/\">3-way ball valve, L-port or T-port (MV-3M)<\/a><\/td><td>CF8M (316), in stock<\/td><td>CF8 (304), made to order<\/td><\/tr><tr><td><a href=\"https:\/\/ballvalves.tw\/ru\/%d0%bf%d1%80%d0%be%d0%b4%d1%83%d0%ba%d1%82\/%d1%81%d0%b0%d0%bd%d0%b8%d1%82%d0%b0%d1%80%d0%bd%d1%8b%d0%b9-%d1%80%d1%83%d1%87%d0%bd%d0%be%d0%b9-%d1%88%d0%b0%d1%80%d0%be%d0%b2%d0%be%d0%b9-%d0%ba%d1%80%d0%b0%d0%bd\/\">Sanitary Tri-Clamp ball valve (V-3N)<\/a><\/td><td>CF8M (316), in stock<\/td><td>CF8 (304), made to order<\/td><\/tr><tr><td><a href=\"https:\/\/ballvalves.tw\/ru\/%d0%bf%d1%80%d0%be%d0%b4%d1%83%d0%ba%d1%82\/%d1%80%d1%83%d1%87%d0%bd%d0%be%d0%b9-%d1%84%d0%bb%d0%b0%d0%bd%d1%86%d0%b5%d0%b2%d1%8b%d0%b9-%d1%88%d0%b0%d1%80%d0%be%d0%b2%d0%be%d0%b9-%d0%ba%d1%80%d0%b0%d0%bd\/\">Flanged ball valve, Class 150\/300 and JIS 10K\/20K<\/a><\/td><td>CF8 (304) or CF8M (316)<\/td><td>State the grade on the enquiry<\/td><\/tr><tr><td><a href=\"https:\/\/ballvalves.tw\/ru\/%d0%bf%d1%80%d0%be%d0%b4%d1%83%d0%ba%d1%82\/%d1%84%d0%b8%d0%bb%d1%8c%d1%82%d1%80-%d1%82%d0%b8%d0%bf%d0%b0-y-800-wog\/\">Y strainer, 800 WOG<\/a><\/td><td>CF8M (316) body and bonnet, in stock<\/td><td>CF8 (304), made to order<\/td><\/tr><tr><td><a href=\"https:\/\/ballvalves.tw\/ru\/%d0%bf%d1%80%d0%be%d0%b4%d1%83%d0%ba%d1%82\/%d0%be%d0%b1%d1%80%d0%b0%d1%82%d0%bd%d1%8b%d0%b9-%d0%ba%d0%bb%d0%b0%d0%bf%d0%b0%d0%bd-%d1%81-%d1%84%d0%bb%d0%b0%d0%bd%d1%86%d0%b5%d0%bc-304\/\">Flanged swing check valve<\/a><\/td><td>CF8 (304), in stock<\/td><td>CF8M (316), made to order<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">The seal-welded two-piece series stocks both grades, while the MxF two-piece ball valve and the flanged swing check valve stock CF8 and make CF8M to order. The grade belongs on the enquiry.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Checking the delivery: the material test report and the marking on the body<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Two things confirm the grade when the valves arrive: the material test report for the castings and the marking on the body. Read both against the order. A magnet, a surface colour or the word &#8220;316&#8221; in the supplier&#8217;s description confirms nothing on its own.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A material test report, usually shortened to MTR, ties a casting to the standard it was produced to. ASTM A703, the general requirements that A351 castings are produced under, requires the manufacturer to certify that the material was made, sampled, tested and inspected to the specification. As applicable, the certificate also states the specification and grade, the heat number or a serial number traceable to it, the chemical analysis of the heat and the mechanical test results. The heat-treatment condition is not on A703&#8217;s list of required items. We supply a material test report for the castings on request; say so on the enquiry if your quality system needs the chemistry on file before the valves are accepted.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img fetchpriority=\"high\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/ballvalves.tw\/wp-content\/uploads\/2026\/10\/cf8m-reading-material-certificate-1024x683.webp\" alt=\"Magnifying loupe held over a printed chemical composition table\" class=\"wp-image-5325\" srcset=\"https:\/\/ballvalves.tw\/wp-content\/uploads\/2026\/10\/cf8m-reading-material-certificate-1024x683.webp 1024w, https:\/\/ballvalves.tw\/wp-content\/uploads\/2026\/10\/cf8m-reading-material-certificate-300x200.webp 300w, https:\/\/ballvalves.tw\/wp-content\/uploads\/2026\/10\/cf8m-reading-material-certificate-768x512.webp 768w, https:\/\/ballvalves.tw\/wp-content\/uploads\/2026\/10\/cf8m-reading-material-certificate-18x12.webp 18w, https:\/\/ballvalves.tw\/wp-content\/uploads\/2026\/10\/cf8m-reading-material-certificate-600x400.webp 600w, https:\/\/ballvalves.tw\/wp-content\/uploads\/2026\/10\/cf8m-reading-material-certificate.webp 1536w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Four checks take a few minutes. Confirm the grade on the report matches the order: CF8M, and the standard you named if you asked for one. Confirm each element sits inside the window in the composition table later in this guide, with particular attention to molybdenum between 2.0 and 3.0 percent, since that is the element that makes CF8M what it is. Confirm the heat number on the report corresponds to the lot you received. And if the report lists mechanical results, confirm they clear the A351 minimums given later in this guide.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Certificates are also classified by EN 10204, the European standard for inspection documents, and the type matters more than the title on the page. A type 2.1 document is a declaration of compliance with the order, with no test results. A type 2.2 test report carries results from non-specific inspection, which may come from other material made by the same process. A type 3.1 inspection certificate carries results from tests on the material actually supplied, validated by a manufacturer&#8217;s representative independent of the production department. A type 3.2 certificate adds an inspector appointed by the purchaser or by regulation, as the <a href=\"https:\/\/bssa.org.uk\/bssa_articles\/bsen-10204-test-certificates-for-stainless-steel-products\/\" target=\"_blank\" rel=\"noopener\">British Stainless Steel Association explains<\/a>. If your quality system requires a particular type, state it on the enquiry so it can be confirmed before the order is placed.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The marking on the body is the other check. Valve markings follow <a href=\"https:\/\/msshq.org\/page\/SP25\" target=\"_blank\" rel=\"noopener\">MSS SP-25<\/a>, the Manufacturers Standardization Society&#8217;s standard marking system for valves, fittings, flanges and unions, which identifies the manufacturer, the rating designation, the materials of construction and any special service limitations. The material appears as a grade designation, and ASTM A703 gives CF8M as the grade symbol for a cast 316 body. Ours are cast with the familiar wrought number instead: a YZNG TRONG body reads 316 or 304 together with the size and, on some series, the pressure rating, while the certificate for the same casting reads CF8M or CF8. The certificate is the document that fixes the grade. The marking lets you check on the shop floor that the grade family and the size cast on the valve match the order.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Common mistakes when specifying CF8M<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Five mistakes that are easy to make with CF8M, and cheap to prevent:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Rejecting a CF8M certificate because the order said 316.<\/strong> The certificate is correct; the order was written in the wrought designation. Add the casting grade to the order template and it stops happening.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Treating the material code as a rating.<\/strong> CF8M says nothing about pressure or temperature. Write the valve&#8217;s rating and the seat material as their own lines, and remember that the seat, or the actuator on an automated valve, sets the temperature ceiling first.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Assuming molybdenum solves every corrosion problem.<\/strong> CF8M resists chloride pitting far better than CF8, but the resistance has limits that depend on chloride concentration, temperature and whether the medium stagnates in crevices. Put the medium and the temperature on the enquiry and let the supplier confirm the grade against them.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Treating EN 1.4408 and CF8M as interchangeable on molybdenum.<\/strong> CF8M allows 2.0 to 3.0 percent molybdenum, while EN 1.4408 stops at 2.5. A CF8M heat with 2.7 percent molybdenum is still CF8M but is outside 1.4408, so a European drawing that calls for 1.4408 needs the certificate checked against the EN grade, not A351.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Missing the M.<\/strong> CF8 and CF8M look alike on a certificate and on a casting marked with the grade symbol, and the single letter is the entire difference. When a valve arrives, read the marking on the body and the certificate against the order before the valve goes into the line.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">CF8M composition and strength: what ASTM A351 requires<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">ASTM A351 requires CF8M to contain 18.0 to 21.0 percent chromium, 9.0 to 12.0 percent nickel and 2.0 to 3.0 percent molybdenum, with carbon at 0.08 percent maximum and manganese and silicon each at 1.50 percent maximum. Each element has a window rather than a single value, so two certificates for the same grade will show different numbers and both can be right. The table compares CF8M with CF8, the grade without the molybdenum addition, and with wrought 316, because all three turn up on paperwork for the same valve.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Element (weight %)<\/th><th>CF8M (cast 316)<\/th><th>CF8 (cast 304)<\/th><th>Wrought 316 (UNS S31600)<\/th><\/tr><\/thead><tbody><tr><td>Carbon (C), max<\/td><td>0.08<\/td><td>0.08<\/td><td>0.08<\/td><\/tr><tr><td>Manganese (Mn), max<\/td><td>1.50<\/td><td>1.50<\/td><td>2.00<\/td><\/tr><tr><td>Silicon (Si), max<\/td><td>1.50<\/td><td>2.00<\/td><td>0.75<\/td><\/tr><tr><td>Phosphorus (P), max<\/td><td>0.040<\/td><td>0.040<\/td><td>0.045<\/td><\/tr><tr><td>Sulfur (S), max<\/td><td>0.040<\/td><td>0.040<\/td><td>0.030<\/td><\/tr><tr><td>Chromium (Cr)<\/td><td>18.0 to 21.0<\/td><td>18.0 to 21.0<\/td><td>16.0 to 18.0<\/td><\/tr><tr><td>Nickel (Ni)<\/td><td>9.0 to 12.0<\/td><td>8.0 to 11.0<\/td><td>10.0 to 14.0<\/td><\/tr><tr><td>Molybdenum (Mo)<\/td><td>2.0 to 3.0<\/td><td>0.50 max<\/td><td>2.00 to 3.00<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">The CF8M and CF8 limits are those of ASTM A351\/A351M as tabulated in the same SFSA summary of casting specifications; the wrought column gives the UNS S31600 limits specified in ASTM A240 for plate, sheet and strip. ASTM A743, the general-purpose casting specification, allows CF8M silicon up to 2.00 percent, so the silicon limit depends on which specification the casting was ordered to.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Three differences are worth knowing before you compare a casting certificate with a wrought data sheet. Chromium runs higher and nickel lower in the cast grade. Silicon is allowed up to 1.50 percent in the casting against 0.75 in wrought 316. And a CF8M casting is balanced to contain some ferrite inside its austenite, on purpose: SFSA gives strength, weldability and corrosion resistance in certain environments as the reasons. Ferrite is magnetic. That is why a cast stainless body can show a faint pull on a magnet while wrought 316, which is normally fully austenitic, usually does not, and why a magnet is the wrong tool for checking a grade.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">On strength, A351 requires CF8M castings to reach a minimum tensile strength of 70 ksi (485 MPa), a minimum yield strength of 30 ksi (205 MPa) and at least 30 percent elongation. CF8 has the same tensile and yield minimums; the difference between the two grades is corrosion resistance, not strength.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Property (ASTM A351)<\/th><th>CF8M<\/th><th>CF8<\/th><\/tr><\/thead><tbody><tr><td>Tensile strength, min<\/td><td>70 ksi (485 MPa)<\/td><td>70 ksi (485 MPa)<\/td><\/tr><tr><td>Yield strength at 0.2 % offset, min<\/td><td>30 ksi (205 MPa)<\/td><td>30 ksi (205 MPa)<\/td><\/tr><tr><td>Elongation in 2 in. (50 mm), min<\/td><td>30 %<\/td><td>35 %<\/td><\/tr><tr><td>Heat treatment required by A351<\/td><td>Heat to 1900 \u00b0F (1040 \u00b0C) minimum, then quench in water or rapid cool<\/td><td>Same<\/td><\/tr><tr><td>UNS number<\/td><td>J92900<\/td><td>J92600<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">A351 also requires every casting to be solution heat treated: heated to at least 1900 \u00b0F (1040 \u00b0C), held until the section is uniformly at temperature, then quenched in water or cooled rapidly by other means. SFSA&#8217;s data sheet gives maximum corrosion resistance as the aim of the treatment.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">These minimums describe the alloy. The valve&#8217;s pressure rating comes from its design: wall thickness, joint design and seat material. Two valves cast from identical CF8M can carry different ratings, which is why the rating is its own line in the specification. Our guide to <a href=\"https:\/\/ballvalves.tw\/ru\/%d0%bd%d0%be%d0%bc%d0%b8%d0%bd%d0%b0%d0%bb%d1%8c%d0%bd%d0%be%d0%b5-%d0%b4%d0%b0%d0%b2%d0%bb%d0%b5%d0%bd%d0%b8%d0%b5-%d0%b2-%d1%81%d0%b8%d1%81%d1%82%d0%b5%d0%bc%d0%b5-wog\/\">what 1000 WOG actually means<\/a> covers that side.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">CF8M or CF8: choosing the grade<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">CF8M and CF8 differ in molybdenum: 2.0 to 3.0 percent in CF8M against 0.50 percent maximum in CF8. Molybdenum is what raises resistance to pitting and crevice corrosion in chloride-bearing media, so chloride exposure is the usual reason to choose CF8M; acidity or alkalinity on its own does not decide it. Outokumpu expresses the effect as PRE = %Cr + 3.3 \u00d7 %Mo + 16 \u00d7 %N, and its <a href=\"https:\/\/www.outokumpu.com\/-\/media\/files\/products\/supra\/outokumpu-supra-range-datasheet.pdf?revision=7a909396-d1f3-4d36-9c1c-99606be41fd2&amp;modified=20251117111951\" target=\"_blank\" rel=\"noopener\">data sheet for its 316-type grades<\/a> groups its 304-type grades at PRE 17 to 22 and its 316-type grades at 22 to 26, with standard 316 at 24. ASTM A351 sets no PRE value for CF8M. Our own arithmetic from its minimums (18 percent chromium, 2 percent molybdenum, nitrogen ignored) gives about 24.6, a rough comparison only: Euro Inox notes that the formula applies to homogeneous material in the as-delivered condition, and a casting carries ferrite islands. Typical media for each grade are covered in our article on <a href=\"https:\/\/ballvalves.tw\/ru\/ball-valve-manufacturing\/\">how our ball valves are manufactured<\/a>. If you are unsure, send us the medium, the concentration and the temperature before you write the grade line.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">CF8M equivalent grades in JIS, EN and UNS<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The closest CF8M equivalents are JIS G 5121 SCS14A in Japan, EN 10213 and EN 10283 grade 1.4408 (GX5CrNiMo19-11-2) in Europe and, on the wrought side, UNS S31600 (AISI 316), EN 1.4401 and JIS SUS 316. SCS14A carries the same chemical limits as A351 CF8M. The others overlap heavily but are not identical, and a casting certified to one standard does not automatically conform to another.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>\u0421\u0442\u0430\u043d\u0434\u0430\u0440\u0442\u043d\u044b\u0439<\/th><th>Grade designation<\/th><th>Product form<\/th><th>\u041f\u0440\u0438\u043c\u0435\u0447\u0430\u043d\u0438\u044f<\/th><\/tr><\/thead><tbody><tr><td>ASTM A351 \/ A743<\/td><td>CF8M (UNS J92900)<\/td><td>Casting<\/td><td>Reference grade: Cr 18.0 to 21.0, Ni 9.0 to 12.0, Mo 2.0 to 3.0, C 0.08 max<\/td><\/tr><tr><td>JIS G 5121<\/td><td>SCS14A<\/td><td>Casting<\/td><td>Same composition window as A351 CF8M. The related grade SCS14 has a different window (Cr 17.0 to 20.0, Ni 10.0 to 14.0, Si and Mn up to 2.00), so name the A grade when you mean CF8M<\/td><\/tr><tr><td>EN 10213 \/ EN 10283<\/td><td>1.4408 (GX5CrNiMo19-11-2)<\/td><td>Casting<\/td><td>Close match, not identical: C 0.07 max, Cr 18 to 20, Ni 9 to 12, Mo 2.0 to 2.5 against 2.0 to 3.0 for CF8M<\/td><\/tr><tr><td>UNS \/ AISI (limits per ASTM A240)<\/td><td>S31600 (316)<\/td><td>Wrought (A240: plate, sheet and strip)<\/td><td>Cr 16.0 to 18.0, Ni 10.0 to 14.0, Mo 2.00 to 3.00, Si 0.75 max<\/td><\/tr><tr><td>EN material number<\/td><td>1.4401<\/td><td>Wrought<\/td><td>European wrought 316<\/td><\/tr><tr><td>JIS (wrought)<\/td><td>SUS 316<\/td><td>Wrought<\/td><td>Japanese wrought 316<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">The cast and wrought rows follow the Australian Stainless Steel Development Association&#8217;s <a href=\"https:\/\/www.assda.asn.au\/stainless-steel\/grade-selection\/316-the-first-step-up\" target=\"_blank\" rel=\"noopener\">table of approximate equivalent designations<\/a>, which places UNS J92900, ASTM A743 CF-8M and material number 1.4408 in one casting row, and S31600, 316, 1.4401 and SUS 316 in the wrought row. The composition windows for SCS14A and 1.4408 are taken from the published tables of those grades. When a drawing from one region is quoted by a supplier in another, name the standard you need the certificate written against and let the supplier confirm that the heat meets it.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">\u0427\u0430\u0441\u0442\u043e \u0437\u0430\u0434\u0430\u0432\u0430\u0435\u043c\u044b\u0435 \u0432\u043e\u043f\u0440\u043e\u0441\u044b<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">What is CF8M material?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">CF8M is a cast austenitic stainless steel grade defined in ASTM A351 (for pressure-containing castings) and ASTM A743 (for general corrosion-resistant castings). It contains about 18 to 21 percent chromium, 9 to 12 percent nickel and 2 to 3 percent molybdenum, with carbon limited to 0.08 percent, and it is the cast counterpart of wrought 316 stainless steel. In ASTM terms, a valve body, pump casing or fitting sold as 316 stainless steel is normally CF8M when it is a casting. Its UNS number is J92900.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">What does CF8M mean on a valve?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">It means the cast pressure-containing parts, usually the body and the end caps and sometimes the ball, are made of CF8M, the cast form of 316 stainless steel. It does not tell you the pressure rating, the temperature limit, the seat material, the stem grade or the thread standard; those are separate lines of the specification. On our valves the body is cast with 316 or 304 and the size, while the certificate names the casting grade, CF8M or CF8, so check each one against the order.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Is CF8M the same as 316 stainless steel?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">CF8M is the cast form of the 316 alloy family, so a CF8M valve body is a 316 stainless steel body in the ordinary commercial sense. The two designations are not interchangeable on paper, however: 316 refers to wrought products such as plate, bar and pipe, while CF8M refers to castings, and the composition windows differ slightly to suit each process. A certificate for a cast body will say CF8M, so a drawing for a cast body should name the casting grade and, if your quality system requires it, the specification it is to be certified to.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">How do I write CF8M on a purchase order or drawing?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Write the casting grade against the cast parts, not the wrought name on its own: &#8220;Body, end caps and ball: CF8M (cast 316)&#8221;, followed, if your quality system requires it, by the specification the certificate is to be written against, such as ASTM A351. Then add the lines the grade does not cover: stem material, seat material and working temperature, pressure rating, end connection with its thread standard, and the material test report. The description line can still say 316 stainless steel; the grade line is the one the inspector matches to the certificate.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">What is the equivalent of CF8M in JIS and EN standards?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The usual equivalents are JIS G 5121 SCS14A in Japan and EN 1.4408 (GX5CrNiMo19-11-2, covered by EN 10213 and EN 10283) in Europe; the wrought counterparts are UNS S31600, AISI 316, EN 1.4401 and JIS SUS 316. SCS14A has the same composition window as ASTM A351 CF8M. EN 1.4408 is close but not identical: its carbon limit is 0.07 percent and its molybdenum range is 2.0 to 2.5 percent, against 2.0 to 3.0 percent for CF8M. Treat all of these as approximate equivalents and name the standard you need the certificate written against on the order.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Summary<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">CF8M material is cast 316: an ASTM A351 grade with 2 to 3 percent molybdenum, the same strength minimums as CF8 and much better resistance to chloride pitting, matching JIS SCS14A and close to EN 1.4408. To specify a CF8M ball valve, write the casting grade for the body, end caps and ball, add the specification the certificate should cite if your quality system requires it, and then add the stem, the seat with its temperature limit, the pressure rating, the end connection with its thread standard, and the documents you want with the delivery. When the valves arrive, check the material test report and the marking on the body against the order.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Our ball valve bodies, end caps and balls are investment cast in CF8 and CF8M and CNC machined. A material test report is available on request, and every finished valve is leak tested and checked dimensionally at our own factory in Taiwan before it ships. If you are specifying a stainless steel ball valve and want the grade line checked against your drawing, send us the drawing or the line conditions.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/ballvalves.tw\/ru\/%d0%b7%d0%b0%d0%bf%d1%80%d0%be%d1%81%d0%b8%d1%82%d1%8c-%d1%80%d0%b0%d1%81%d1%86%d0%b5%d0%bd%d0%ba%d0%b8\/\">\u0417\u0430\u043f\u0440\u043e\u0441\u0438\u0442\u044c \u0440\u0430\u0441\u0446\u0435\u043d\u043a\u0438 \u2014 \u043e\u0442\u0432\u0435\u0442 \u0432 \u0442\u0435\u0447\u0435\u043d\u0438\u0435 24 \u0447\u0430\u0441\u043e\u0432 \u2192<\/a><\/p>","protected":false},"excerpt":{"rendered":"<p>CF8M material is the ASTM casting grade for 316-type stainless steel: 18 to 21 percent chromium, 9 to 12 percent nickel, 2 to 3 percent molybdenum, with carbon held to 0.08 percent. To specify a CF8M ball valve, write that casting grade against the cast parts, then add the five things the grade does not [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":5324,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[48],"tags":[],"class_list":["post-5323","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-how-to-guides-tutorials"],"_links":{"self":[{"href":"https:\/\/ballvalves.tw\/ru\/wp-json\/wp\/v2\/posts\/5323","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ballvalves.tw\/ru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ballvalves.tw\/ru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ballvalves.tw\/ru\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/ballvalves.tw\/ru\/wp-json\/wp\/v2\/comments?post=5323"}],"version-history":[{"count":3,"href":"https:\/\/ballvalves.tw\/ru\/wp-json\/wp\/v2\/posts\/5323\/revisions"}],"predecessor-version":[{"id":5369,"href":"https:\/\/ballvalves.tw\/ru\/wp-json\/wp\/v2\/posts\/5323\/revisions\/5369"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ballvalves.tw\/ru\/wp-json\/wp\/v2\/media\/5324"}],"wp:attachment":[{"href":"https:\/\/ballvalves.tw\/ru\/wp-json\/wp\/v2\/media?parent=5323"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ballvalves.tw\/ru\/wp-json\/wp\/v2\/categories?post=5323"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ballvalves.tw\/ru\/wp-json\/wp\/v2\/tags?post=5323"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}