10B35 is the SAE 1035 base grade with a small boron addition: 0.32–0.38% carbon, 0.60–0.90% manganese and 0.0005–0.003% boron. The boron raises hardenability, so a medium carbon steel hardens through in thick fastener sections. It is used for Class 10.9 and 12.9 bolts, high-strength cold-forged fasteners, hex socket screws and studs.
OneKaizen supplies 10B35 as wire rods in Ø 5.5–40 mm, bright wires in Ø 1.5–37 mm, round bars in Ø 16–500 mm and bright bars in Ø 8–160 mm, sourced from Indian and international mills. Delivery condition is your choice: hot rolled wire rod, spheroidise annealed for cold heading, drawn, or hot rolled bars. Every consignment ships with a mill test certificate.
EQUIVALENT GRADES
10B35 Equivalents
Direct means the same grade under another name. Close means the same alloy concept with slightly different limits, commonly substituted. Approximate means similar use with real differences: check with us before substituting.
| Standard | Designation | Match |
|---|---|---|
| AISI/SAE | 10B35 | Direct |
| JIS | SWRCHB237 | Approximate |
10B35 Chemical Composition
Per SAE J403 (SAE 10B35) - base grade 1035 plus boron
| Element | Range, wt % | Range chart |
|---|---|---|
| C | 0.32 – 0.38 | |
| Mn | 0.6 – 0.9 | |
| B | 0.0005 – 0.003 |
Delivery Condition and Heat Treatment
10B35 is normally spheroidise annealed before cold heading, which softens the steel and improves its cold forgeability. After forming, the fasteners are austenitised, quenched and tempered to the strength class required, including Class 12.9.
Boron works only in very small amounts and only when it is free in the steel, so the mill protects it from nitrogen with titanium or aluminium. Check the chemistry of each heat, and avoid long holds at high temperature, which weaken the boron effect.
Welding is not the normal route for this grade. It is used for cold-headed and forged parts, and the high hardenability makes welded joints hard and crack-prone unless pre-heat and post-heat are controlled.
What We Supply 10B35 In
Where 10B35 Is Used
Industries: Fasteners, Automotive, Agricultural equipment, Construction and mining equipment, Cold forging
Compare 10B35 with Similar Grades
10B35 Questions
Is 10B35 the same as SWRCHB237?
No. JIS SWRCHB237 is an approximate match only. Both are boron-treated cold heading steels at a similar carbon level, but the limits differ. Tell us which one your drawing calls for and we confirm what the mill can supply.
Is there an EN equivalent of 10B35?
There is no exact EN equivalent. EN 10263-4 boron grades are comparable in purpose, but they are not interchangeable without checking the chemistry against your specification.
What is the difference between 10B35 and 10B33?
10B35 has slightly higher carbon (0.32–0.38% against 0.30–0.36%) and slightly lower manganese. It reaches higher strength after quenching and tempering, so it suits Class 12.9. 10B33 gives more cold-forming margin and suits Class 10.9.
Can 10B35 be heat treated or welded?
Yes, it is quenched and tempered after cold heading to reach the strength class. We do not recommend welding without controlled pre-heat and post-heat.
What is 10B35 used for?
Class 10.9 and 12.9 bolts, high-strength cold-forged fasteners, hex socket screws and studs, mainly for automotive, agricultural, construction and mining equipment. OneKaizen also machines parts to drawing through partner machine shops.
What is the minimum order for 10B35?
3 tonnes, flexible depending on size and your situation. Send us your size, condition and quantity and we confirm availability and delivery.
What is 10B35 equivalent to?
10B35 is the same grade as AISI/SAE 10B35.
In which forms do you supply 10B35?
OneKaizen supplies 10B35 as Wire Rods, Bright Wires, Round Bars, Bright Bars, delivered across India and exported to buyers abroad.
Do you supply 10B35 with a mill test certificate?
Yes. Every lot ships with an EN 10204 3.1 mill test certificate showing chemistry and mechanical properties, traceable to the heat number.
Data compiled by the OneKaizen metallurgy team from the standards named above. Updated 27 October 2026. Equivalents are nearest matches; confirm critical substitutions against the governing standard and mill certificate.