Alloy Steel Products: B8/B8M/F55 Fasteners & P11/P22/P91 Chrome-Moly Pipes, Fittings & Sheets
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Fasteners: A193/A194 B8 · B8M · B8T · B8C · B8MLCUN · F51 · F53 · F55 · Gr 660 · Chrome-Moly: P5 · P11 · P22 · P91 · WP & F forms
Aashish Metals supplies alloy steel in the two forms this market actually asks for: high-specification bolting and chrome-moly pipework. On the fastener side we hold the ASTM A193 and A194 B-series and the F-grades, and our Alloy Steel F55 fasteners and B8 fasteners are the busiest lines, cut and certified for high-temperature and corrosive bolting. Every item ships with mill test certificates. If you already know the grade and the form, the tables below take you straight to the page.
The other half of alloy steel is chrome-moly, the chromium-molybdenum grades that hold strength at high temperature in power and refinery service. We stock these as pipes, fittings and sheets from P5 through P22 pipes & tubes to the high-parameter P91. The two families share a name and almost nothing else, so this page keeps them clearly separated and routes you to whichever one you came for.
Two Families of Alloy Steel
| Family | What it is | Bought for |
|---|---|---|
| Bolting (B-series, F-grades) | ASTM A193/A194 bolting grades: B8, B8M, B8T, B8C, B8MLCUN and the F-grades F51, F53, F55 | Flange, pressure and high-temperature bolting where a plain carbon bolt is not enough |
| Chrome-Moly (P/T/F/WP) | Chromium-molybdenum grades: P5, P11, P22, P91 and their F forging and WP fitting forms | Power-plant and refinery pipework that must hold strength at high temperature |
Alloy Steel Fasteners: B8, B8M, B8T & F-Grades
| Grade | What it is | Best for |
|---|---|---|
| B8 / B8 Cl.2 | A193 Grade B8, essentially 304 stainless bolting, carbide-solution treated | General high-temperature and corrosive flange bolting |
| B8M / B8M Cl.2 | A193 Grade B8M, essentially 316 stainless, added molybdenum | Chloride and marine bolting where B8 would pit |
| B8T / B8C | Titanium-stabilised (B8T) and niobium-stabilised (B8C) variants | Elevated-temperature bolting resisting sensitisation |
| B8MLCUN | High-alloy grade for aggressive chemical bolting | Severe corrosive service beyond B8M |
| F51 / F53 / F55 | Duplex and super-duplex forging grades (S31803, S32750, S32760) | High-strength, chloride-resisting bolting and forged components |
| Grade 660 / B16 | Age-hardened (A286, Gr 660) and chrome-moly B16 bolting | High-strength high-temperature bolting |
Chrome-Moly Grades: P11, P22, P91 & F/WP Fittings
| Grade | Nominal | Bought for |
|---|---|---|
| P5 / T5 / WP5 / F5 | 5Cr-0.5Mo | Refinery heaters and high-sulphur service |
| P11 / WP11 / F11 | 1.25Cr-0.5Mo | Lower-temperature power and process pipework |
| P22 / WP22 / F22 | 2.25Cr-1Mo | The common high-temperature boiler and refinery grade |
| P9 / WP9 / F9 | 9Cr-1Mo | Higher-temperature and sulphidation service |
| P91 / WP91 / F91 | 9Cr-1Mo-V-Nb | High-parameter power boilers, the top of the creep ladder |
Alloy Steel Product Forms
| Form | What we hold |
|---|---|
| Fasteners | Stud bolts, hex bolts, nuts and washers across the B-series, F-grades, Grade 660 and B16 |
| Pipes & Tubes | Seamless chrome-moly pipe and tube in P5, P11, P22, P9, P91 |
| Buttweld Fittings | WP5, WP11, WP22, WP9, WP91 elbows, tees, reducers and caps |
| Forged Fittings | F5, F11, F22, F9, F91 threaded and socket-weld fittings and flanges |
| Sheets & Plates | Chrome-moly grade sheet and plate to order |
How to Choose the Right Alloy Steel Grade
- For bolting, follow the flange or vessel spec: it will name B8, B8M or an F-grade directly. B8 for general high-temperature, B8M for chlorides, F55 and the duplex grades for high-strength chloride service.
- For chrome-moly pipe, follow the design temperature: P11 and P22 for most boiler and refinery heat, P91 for high-parameter power plant, P5 and P9 where sulphidation governs.
- Match the fitting to the pipe: a P22 line takes WP22 buttweld and F22 forged fittings, so the whole joint stays one grade.
- If it is really stainless or carbon: B8-family bolting relates to our stainless range, and the chrome-moly grades sit one step above carbon steel.
Quality, Certification & Dispatch
Every order ships with an EN 10204 mill test certificate, heat-number traceable, with positive material identification available and, on bolting, hardness and mechanical test reports to the A193 or A194 requirement. Chrome-moly is air-hardening, so where fittings or welded assemblies need post-weld heat treatment the hardness is checked to confirm it was effective, and IBR Form certification is arranged for boiler-code work at order stage. Third-party witness through BV, SGS or TUV is available. Fasteners in common grades ship quickly from stock; chrome-moly pipe and fittings are confirmed on enquiry. Send the grade, the form and the quantity and the quote comes back with the certification built in.
Alloy Steel Products: Frequently Asked Questions
Two families. For bolting, the ASTM A193/A194 B-series (B8, B8M, B8T, B8C, B8MLCUN), the F-grades (F51, F53, F55), Grade 660 and B16, as stud bolts, hex bolts, nuts and washers. For pipework, the chrome-moly grades P5, P11, P22, P9 and P91 with their WP fitting and F forging forms, as pipes, fittings and sheets. If a grade or form is not listed, ask, because we hold more than the site shows.
The molybdenum. ASTM A193 Grade B8 is essentially 304 stainless at bolt specification, for general high-temperature and corrosive flange bolting. B8M is essentially 316, with added molybdenum for chloride and marine service where B8 would pit. Both are carbide-solution treated, with Class 2 versions strain-hardened for higher strength. Follow the flange or vessel specification, which will name the grade.
Chromium content and temperature capability. P11 is 1.25Cr-0.5Mo for lower-temperature power and process pipework, P22 is 2.25Cr-1Mo and is the common high-temperature boiler and refinery grade, and P91 is a 9Cr-1Mo-V-Nb grade at the top of the creep ladder for high-parameter power boilers. Match the grade to the design temperature, and use the matching WP and F forms for fittings.
Usually yes. Chrome-moly grades are air-hardening, so welding requires preheat, matching filler and post-weld heat treatment, with a hardness check to confirm the PWHT was effective. This matters most on P22 and P91 in boiler and refinery service. We arrange the heat treatment and IBR certification where the code requires it at order stage.
Yes, on every order. Each ships with an EN 10204 mill test certificate that is heat-number traceable, with mechanical and hardness test reports to the ASTM A193 or A194 requirement, positive material identification, and third-party witness inspection available at order stage. It is the assurance the grade and class on the certificate match what is in the box.
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