DIN 931 Hex Bolt half thread Carbon Steel Grade 8.8 | Zinc Plated M6–M36
Product Introduction
Walk through our plant and you'll see why we treat the hex bolt as a precision part, not a commodity. The wire rod goes into a cold header, the head is formed in one hit, then the thread gets rolled — not cut. Rolling keeps the grain flow running through the thread roots, which is exactly where a bolt loses its fatigue life if you cut corners. In a vibrating joint, that difference shows up fast.
half thread means the thread runs from under the head all the way to the tip. There's no plain shank section, so the half length carries the load. That makes DIN 931 the right pick for clamping thin material stacks, or anywhere the thread itself has to do the gripping. We hold 6g thread tolerance, and we check it with ring gauges on the line, not just on paper.
Every lot gets hardness and tensile checks before it ships. Material certs go with the order as standard; if you want an SGS report on top, that's routine for us. You tell us the grade, the finish, and the length. We make it, test it, and pack it. That's the whole system.
Full Specification Table
|
Parameter |
Specification |
|
Standard |
DIN 931; ISO 4014; ASME B18.2.3.1M |
|
Thread Profile |
Metric coarse, ISO 68-1 |
|
Thread Tolerance |
6g (plated items: pre-plating allowance applied so the finished thread still fits 6g/6H) |
|
Head Form |
Hexagon head, chamfered corners |
|
Property Class |
4.8 / 8.8 / 10.9 / 12.9 (carbon & alloy steel, per ISO 898-1) |
|
Tensile Strength (min) |
400 / 800 / 1040 / 1220 MPa |
|
Yield Strength (min) |
340 / 640 / 940 / 1100 MPa |
|
Hardness |
8.8: 22 – 32 HRC; 10.9: 32 – 39 HRC; 12.9: 39 – 44 HRC |
|
Materials |
4.8: C1022A carbon steel; 8.8: 35K / SCM435 (alloy steel required > M16); 10.9 / 12.9: SCM435 alloy steel; SS304 (A2) / SS316 (A4) per ISO 3506-1 |
|
Finish Options |
Plain; Zinc (blue / yellow / black); Hot-Dip Galvanized; Black Oxide; E-coat; Dacromet |
|
Coating Thickness |
E-coat 18 – 25 μm; Zinc 5 – 8 μm; HDG 45 – 85 μm |
|
Salt Spray (typical) |
Zinc 72 – 120 h; E-coat 200 h+; Hot-dip galvanized 500 h+ — per ASTM B117 / ISO 9227; typical values, dependent on finish type and coating thickness |
|
Testing |
Hardness, tensile and proof load per ISO 898-1; salt spray per ASTM B117 / ISO 9227; dimensional gauging |
|
Packaging |
Export cartons and pallets; size-labeled layers; packing photos on request |
|
OEM / ODM |
Custom lengths, laser marking, mixed-size kits, private packaging |
Size Chart
|
Size |
Thread Pitch (mm) |
Across Flats (mm) |
Head Height (mm) |
Stock Length (mm) |
Wrench (mm) |
|
M6 |
1.0 |
10 |
4.0 |
12 – 60 |
10 |
|
M8 |
1.25 |
13 |
5.3 |
16 – 80 |
13 |
|
M10 |
1.5 |
16 |
6.4 |
20 – 100 |
16 |
|
M12 |
1.75 |
18 |
7.5 |
25 – 120 |
18 |
|
M14 |
2.0 |
21 |
8.8 |
30 – 140 |
21 |
|
M16 |
2.0 |
24 |
10.0 |
35 – 160 |
24 |
|
M20 |
2.5 |
30 |
12.5 |
40 – 200 |
30 |
|
M24 |
3.0 |
36 |
15.0 |
50 – 240 |
36 |
|
M30 |
3.5 |
46 |
18.7 |
60 – 300 |
46 |
|
M36 |
4.0 |
55 |
22.5 |
70 – 300 |
55 |
Dimensions per ISO 4014 / DIN 931 (mm). Longer lengths, fine-pitch threads, and inch sizes available on request.
Applications
Why Fasto
Pain Points & Solutions
| Pain Point on the Job Site | How the ME-01 Answers It |
| Screw can't start in hard sheet, crew wastes time pre-drilling | Case-hardened drill point punches its own hole — no pilot drilling, one tool for the whole run |
| Hex head strips out under impact driver | Deeper hex socket and tighter drive fit; the driver engages full-face instead of the corners |
| Washer sinks into soft sheet, panel looks wavy | Full hex washer head spreads bearing load; the panel stays flat |
| Coating fails in coastal or humid climates | Hot-dip galvanized and Dacromet options, salt spray verified per batch up to 300 h |
| Threads slip or jam in thin coated sheet | Point and thread geometry tuned per gauge; we match the size chart to your material |
| Mixed-size orders arrive with wrong counts | Batch traceability and per-size box counts; custom kit packing on request |