DIN 7991 M8 Titanium Bolts – Grade 5 Countersunk Socket Fasteners for High-Performance Applications

DIN 7991 m8 titanium bolts deliver a countersunk hex-socket design engineered for flush, snag-free assembly. Made from Grade 5 titanium (Ti-6Al-4V), they offer tensile strength of 895–1000 MPa and yield strength of ~828 MPa — comparable to Class 8.8/10.9 steel — yet weigh approximately 45% less at just 3.5g per piece. With an M8 × 1.25mm thread, length range of 10–100mm, and a 90° countersunk head angle, these bolts deliver precise self-centering alignment.

Why Choose Our DIN 7991 M8 Titanium Bolts

Sourcing from Baoji Huacan means working with a manufacturer based in China's "Titanium Valley" — Baoji City — with 10+ years of titanium machining experience and 40+ high-precision CNC machines.

We support OEM/ODM orders, custom drawings, and small-to-large batch production. Our annual output exceeds 1,000 tons, backed by ISO 9001 quality management certification.

You get full material traceability, inspection reports, and direct factory pricing — no middlemen.

Technical Specifications

Specification	Technical Details
Standard	DIN 7991 / ISO 10642
Size & Pitch	M8 × 1.25mm
Length	10mm – 100mm
Head & Drive	90° Countersunk Head / Hex Socket
Material	Titanium Grade 5 (Ti-6Al-4V)
Optional Grades	Gr2, Gr5, Gr7, Gr9, Gr23
Tensile Strength	895 – 1000 MPa
Yield Strength	~828 MPa
Density & Weight	4.43 g/cm³ (Approx. 3.5g/pc for reference)
Thread Precision	Class 6g
Surface Finish	Natural Polished, Anodized (Gold, Blue, Rainbow, Black, etc.)
Custom Services	Non-standard sizes available per drawing

Tip			-2	2.5	3	3.5	4	4.5	5	-5.5	6	-7	-8
ds	max=nominal size		2	2.5	3	3.5	4	4.5	5	5.5	6	7	8
ds	min		1.6	2.1	2.6	3.02	3.52	4.02	4.52	5.02	5.52	6.42	7.42
dk	max		4.18	5.08	5.98	6.95	7.95	8.75	9.65	10.75	11.55	13.05	15.05
dk	min		3.42	4.32	5.22	6.05	7.05	7.85	8.75	9.65	10.45	11.95	13.95
k	max		1.2	1.5	1.65	1.93	2.2	2.35	2.5	2.75	3	3.5	4
Socket No.			0	1	1	2	2	2	2	3	3	3	4
M1	≈		-	2.7	2.9	3.9	4.4	4.6	4.8	6.2	6.6	6.8	8.7
M2	≈		-	2.8	3	4	4.2	4.4	5	6.1	6.3	7	8.5
Penetration depth	Type H	min	-	1.25	1.5	1.4	1.9	2.1	2.29	2.31	2.8	2.95	3.9
	Type H	max	-	1.55	1.8	1.9	2.4	2.6	2.79	2.81	3.3	3.53	4.4
	Type Z	min	-	1.48	1.76	1.6	1.85	2.05	2.64	2.46	2.72	3.38	3.86
	Type Z	max	-	1.73	2.01	2.06	2.31	2.51	3.1	2.92	3.18	3.84	4.32

Motorsports & Cycling — Used for brake rotor mounts, frame joints, and bodywork fairings where reduced unsprung weight and aerodynamic drag are critical. The flush head avoids caliper interference.

Marine & Subsea Engineering – Secures deck hardware, hull sensors and ROV components. Unlike stainless steel, these bolts do not pit or crevice corrode under constant saltwater exposure.

Aerospace & UAV Manufacturing – Bonding of carbon fibre composite panels with no danger of galvanic corrosion. Flush head provides laminar airflow across the airframe surfaces.

Medical Devices — Non-magnetic properties make DIN 7991 m8 titanium bolts ideal for MRI-compatible equipment and surgical instrument assemblies.

Bicycle & Cycling

Motorcycle Modification

Automotive Performance & Racing

RC Models & Drones

Marine Equipment

Precision Equipment

lightweight strength: ~45% lighter than similar steel bolts

Flush-mount design: 90° countersunk head prevents surface protrusion for clean, aerodynamic assemblies

Corrosion resistance Ti-6Al-4V is immune to sea water, crevice corrosion and chemical conditions forever

Non-magnetic: Safe for use in MRI and sensitive electronic enclosures

Thermal stability: Operates reliably from cryogenic temperatures to 400°C

Galvanic compatibility: Safe partnering with carbon fibre composite panels, no danger of corrosion

Product Features

Baoji Huacan operates 40+ CNC lathes and machining centers, including gantry systems, capable of handling both prototype and mass production runs.

Annual machining capacity exceeds 1,000 tons. We support the whole upstream supply chain from ingot to completed fastener with our forging operations, including a 4,000-ton hydraulic press.

We produce to ASTM, AMS, DIN, and ISO standards, ensuring every batch meets your target specification.

Each nut starts with verified Grade 5 titanium bar stock, inspected for chemical composition before machining begins.

CNC precision turning handles thread cutting, seat geometry, and outer profile with tight dimensional tolerances. Our 40+ CNC lathes and machining centers ensure consistent repeatability across both small batches and high-volume orders.

After machining, parts go through surface preparation and PVD coating in a vacuum chamber. This process molecularly bonds the black ceramic layer directly to the titanium substrate — no adhesives, no fillers.


Material Preparation	Heading / Forging	Heat Treatment	Precision Machining

Thread Manufacturing	Cleaning	Inspection	Surface Treatment

Every production batch passes a six-stage inspection protocol:

1. Raw material verification — Spectrometer analysis confirms Al (6%) and V (4%) content

2. In-process dimensional checks — Real-time monitoring at each machining stage

3. Thread inspection — Go/No-Go gauges verify 6g tolerance

4. Head angle verification — Optical comparator confirms 90° countersink geometry

5. Mechanical testing — Tensile and hardness testing (HRC 30–34) per DIN/ISO standards

6. Surface & final inspection — Burr-free hex socket check, roughness measurement, and appearance review

Certifications

· ISO 9001 Quality Management System certified

· Material Test Certificates (MTC) available

· EN 10204 3.1 documentation available on request

· Certificate of Conformance (COC) provided with each shipment

You can specify exactly what your application requires:

· Thread: M8 coarse (1.25mm) or fine (1.0mm) pitch; custom thread profiles available

· Length: 10–100mm standard range; custom lengths per drawings

· Material grade: Grade 2, 5, 7, 9, or 23 titanium

· Head type: Countersunk, hex head, socket head — per customer request

· Surface finish: Natural polished, anodized (gold, blue, black, rainbow), PVD coating

· Marking: Laser engraving, part number, custom logo

· OEM/ODM: Full drawing-based manufacturing supported

Method	Details
Inner packaging	Vacuum-sealed bags with desiccants
Outer packaging	Custom foam inserts or wooden crates
Documentation	MTC, COC, labeling for full traceability
Air freight	Available for urgent orders
Sea freight	Available for cost-effective bulk shipments

Q: What installation torque is recommended?

A：Reduce standard M8 steel torque (~24Nm) by 20–30%. Always use anti-seize paste to prevent titanium galling.

Q: Can these bolts pair with aluminum components?

A: Yeah. In moist situations titanium and aluminium may cause galvanic corrosion . An insulating washer or ceramic paste is recommended .

Q: Do you need Grade 5, not Grade 2?

A：M8 socket bolts need to be Grade 5. Grade 2 hex sockets peel at the torque required to effectively seat an M8 bolt.

Q: DIN 7991 or ISO 10642?

A: They are essentially the same for most M8 applications. DIN 7991 heads are a little higher, ISO 10642 has a slightly rounder transition. Check countersink depth for aerospace quality fittings.

Q: Are the products magnetic?

A：No. They are fully non-magnetic, making them suitable for MRI equipment and sensitive navigation housings.