Patriot Bolt machines ASTM A193 Grade B7 fasteners from certified AISI 4140 and 4142 chromium-molybdenum bar, quenched and tempered to the specification. B7 is the most widely used alloy steel grade for pressure flanges, valves and fittings.
This page brings together the B7 fasteners we make, the B7 property limits by diameter, and how B7 compares with the other alloy steel bolting grades.
A193 B7 at a Glance
- Specification
- ASTM A193 / ASME SA193 Grade B7
- Material
- AISI 4140 / 4142, UNS G41400 / G41420
- Strength
- 125 ksi min tensile, 105 ksi min yield (2-1/2 in and under)
- Matching nut
- A194 Grade 2H
- Products
- Stud bolts, heavy hex bolts, nuts
A193 B7 Fasteners We Machine
Choose a product to see its standards and options. Every order ships with mill test reports traceable to the heat.
A193 B7 Stud BoltsFull B7 page
A194 2H Heavy Hex NutsMatching nut
B7 Heavy Hex BoltsMade in B7A193 B7 Mechanical Properties
| Diameter | Tensile, min | Yield (0.2%), min | Hardness, max |
|---|---|---|---|
| 2-1/2 in and under | 125 ksi | 105 ksi | 321 HBW |
| Over 2-1/2 to 4 in | 115 ksi | 95 ksi | 321 HBW |
| Over 4 to 7 in | 100 ksi | 75 ksi | 321 HBW |
Full chemistry is on the A193 B7 stud bolts page.
B7 vs. Other Alloy Steel Bolting Grades
| Grade | Strength (to 2-1/2 in) | Typical use |
|---|---|---|
| A193 B7 | 125 ksi tensile / 105 ksi yield | General flange bolting to about 800 °F |
| A193 B7M | 100 ksi / 80 ksi, 235 HBW max | Sour (H2S) service per NACE MR0175 |
| A193 B16 | 125 ksi / 105 ksi | Steam and hot service to about 1100 °F |
| A320 L7 | 125 ksi / 105 ksi, impact tested at −150 °F | Low-temperature flanges to 2-1/2 in |
Compare all grades in the Fastener Materials Matrix.
A193 B7 Fastener FAQ
What is A193 B7 made of?
B7 is AISI 4140 or 4142 chromium-molybdenum steel, quenched and tempered at 1100 °F minimum.
Which B7 fasteners does Patriot Bolt make?
We machine B7 stud bolts, heavy hex bolts and nuts, as well as custom parts made to your drawing.
Can B7 be used in sour service?
No. NACE MR0175 limits bolting hardness in H2S service. Use B7M studs with 2HM nuts instead.
Do B7 fasteners come with certifications?
Yes. Patriot Bolt is ISO 9001:2015 certified, and every B7 order includes mill test reports traceable to the heat and a certificate of conformance to your purchase order.
Request a Quote
Send us the product, size, specification and quantity, or upload your drawing. Call (281) 581-0176 or request a quote.