Manufacturer of ASTM A193 B8M Stud Bolts
ASTM A193 B8M Fasteners Specification & Properties
As a trusted manufacturer of ASTM A193 B8M Stud Bolts with A194 8M Hex Nuts, we specialize in providing high-quality fasteners designed to meet the most demanding industrial requirements. Made from stainless steel B8M (316), our stud bolts and hex nuts are engineered for superior strength, corrosion resistance, and reliability in high-temperature and high-pressure environments.
ASTM A193 B8M is a stainless steel grade for stud bolts, primarily used in high-temperature, high-pressure, and corrosive environments like chemical processing, marine, and offshore industries. Grade B8M Bolt is made of SS316 round bar.Which offers a superior corrosion resistance compared to B8 (304 stainless steel).
B8M Stud Bolt – Chemical Composition
| Element | Requirement (%) |
|---|---|
| Carbon (C) | ≤ 0.08 |
| Manganese (Mn) | ≤ 2.00 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 |
| Silicon (Si) | ≤ 1.00 |
| Chromium (Cr) | 16.0 – 18.0 |
| Nickel (Ni) | 10.0 – 14.0 |
| Molybdenum (Mo) | 2.0 – 3.0 |
ASTM A193 B8M Fasteners – Mechanical Properties
| Grade | Tensile Strength (MPa / ksi) | Yield Strength (MPa / ksi) | Elongation (%) | Hardness (HRC / HBW) |
|---|---|---|---|---|
| B8M Class 1 (Solution-Annealed) | 515 MPa (75 ksi) min | 205 MPa (30 ksi) min | 30% min | ≤ 223 HBW (95 HRB max) |
| B8M Class 2 (Strain-Hardened) | 860 MPa (125 ksi) min | 620 MPa (90 ksi) min | 15% min | ≤ 321 HBW (35 HRC max) |
🔹 Class 1 → Solution-annealed
🔹 Class 2 → Strain-hardened
There are 2 different classes in ASTM A193 B8M because of different heat treatment meothid.
The class 1 products are carbide solution treated while the class 2 products are strain hardened in addition to the carbide solution treatment
ASTM A193 B8M Fasteners size and standard
ASTM A193 → Standard specification for high-temperature and high-pressure bolting.
ASME B16.5 → Stud bolt dimensions for flange bolting.
ASME B18.2.1 / B18.2.2 → Standard for bolt & nut dimensions.
ASME B1.1 / B1.13M → Unified UNC, UNF & metric thread standards.
ISO 898-1 → Metric equivalent standard for stud bolts.
Size Scope:1/2in to 2 1/2″
Length:customize length upto 3000mm length
Recommended Nuts, & Washer for B8M Fasteners
| Bolt Grade | Nuts | Washers |
| B8M Class 1 | A194 Grade 8M | SS316 |
To produce high quality of ASTM A193 B8M Stud bolt,and A194 8M Hex nuts
Following Inspection and Test plan (ITP) is recommended.
| Item NO | Activity | Activity Details | Acceptance Criteria |
| 1.0 | DOCUMENTS REVIEW / APPROVAL BEFORE PRODUCTION | Check the revision of the SPECs and Standards. | ASTM A193 ASTM A194 Size standards are based on actual orders |
| 1.1 | Technical specification and Standard | Check the revision of the SPECs and Standards. | ASTM A193 ASTM A194 Size standards are based on actual orders |
| 2.0 | MATERIAL INCOMING INSPECTION, VERIFICATION AND REVIEW OF MILL CERTIFICATES | Base Material Incoming Inspection: Mill Certificates Review; | ASTM A193 Table 1 Solution – Strain Hardening condition ASTM A194 Table 1 |
| 2.1 | Base Material Incoming Inspection | Appearance, diameter, length VT, diameter, length | Purchase Order ASTM A193 Table 1 |
| Raw material chemical composition recheck | ASTM A194 Table 1 | ||
| Mechanical performance recheck | |||
| 3.0 | Manufacturing Process Control | Raw Material Cutting: Cutting according to customer Drawing or standard with appropriate allowance. | Customer required length |
| 3.1 | Raw Material Cutting | Cutting according to customer Drawing or standard with appropriate allowance. | Customer required length |
| 3.2 | Chamfering | 1 Pitch x45° | API 6A GRIC API 6A Appendix C |
| 3.3 | Marking | LOGO and Material grade: | ASTM A193 ASTM A194 |
| 3.4 | Thread Rolling and Tapping | According to ASME B1.1 or B1.13M | ASME B1.1 ASME B1.13M |
| 3.5 | Mechanical Property Test | Full – thread studs: 3.5.1. Tensile test at Room Temperature (Per same heat No & Nominal diameter) | ASTM A193 |
| 3.5.2. Hardness test: Test on the tensile test sampling studs. | |||
| Heavy Hex Nuts: 3.5.3. Proof test(d≤1 1/2″): Sampling as per below: | ASTM A194 | ||
| 3.5.4. Hardness test: Sampling as per below: Lot size Sampling ≤800 1 801 – 8000 2 8001 – 22000 3 ＞22000 5 | |||
| 3.6 | Coating | According to BM list | Coating process card |
| 3.7 | Coating Inspection | 3.7.1. Thickness test: ASTM F1337 microscopic exam of the cross – section taken perpendicular to the significant surface | Coating process card |
| 3.7.2. Xylan 1014 Curing test—115C: Curing test for Xylan 1014: Whitford Test Method 115B Xylan 2 Curing test—115C: Curing test for Xylan – 2: Whitford Test Method 115C | |||
| 3.7.3. Adhesion Test—132C: Adhesion Test: Whitford Test Method 132C | |||
| 3.8 | Surface conditions inspection | 100% VT | ASTM A962 / 962M |
| 3.9 | Dimension final check | According to Fastener Inspection Procedure | Based on actual order criteria |
| 4.0 | Packing | Packing: Matching the nuts with studs, then put into carton according to customer requirements. And then put cartons into wooden box with film that against water and moisture. | Contract requirements |
| 4.1 | Packing | Matching the nuts with studs, then put into carton according to customer requirements. And then put cartons into wooden box with film that against water and moisture. | Contract requirements |
| 5.0 | Shipping | Final Documents submission: Mill Certificate | Contract requirements |
| 5.1 | Final Documents submission | Mill Certificate Packing list | Contract requirements |
What is the difference between A193 Grade B8 and Grade B8M?
These bolts are both stainless bolt grade with similar strength requirements but differ in their corrosion resistance. Grade B8 bolts are made from type 304 stainless steel, while Grade B8M bolts are made from a more corrosion-resistant type 316 stainless steel.
ASTM A193 B8M vs B8 Stud Bolts
| Item | B8 (304 SS) | B8M (316 SS) |
|---|---|---|
| Molybdenum | No | Yes |
| Corrosion Resistance | Good | Superior |
| Marine Use | Limited | Excellent |
| Typical Application | General | Offshore / chemical |
ASTM A193 B8M Bolt – Applications
✔ Offshore & Marine Environments (Corrosion resistance in seawater)
✔ Chemical & Petrochemical Plants (Acidic & aggressive chemicals)
✔ Power Plants & Boilers (High-temperature performance)
✔ Food & Pharmaceutical Industry (Hygienic, corrosion-resistant)
Why Choose ASTM A193 B8M Stud Bolts with A194 8M Hex Nuts?
When high strength, durability, and corrosion resistance are non-negotiable, ASTM A193 B8M Stud Bolts and A194 8M Hex Nuts deliver top-tier performance. Engineered to handle the most challenging industrial environments, these fasteners ensure your projects are built to last, even under extreme pressure and temperature conditions.
ASTM A193 B8M stud bolts with ASTM A194 8M hex nuts provide a corrosion-resistant, reliable fastening solution for high-pressure piping systems in aggressive environments. With excellent resistance to chlorides and proven performance in offshore and chemical service, this stainless steel bolting combination is a trusted choice for critical flange connections.
