High Tensile Fasteners

High tensile fasteners are purpose built bolts, screws, nuts, and studs engineered to handle high pulling loads without failure. They are made from heat treated alloy steel or carbon steel and selected high tensile stainless grades. This gives higher tensile strength and stable clamp force in demanding assemblies where standard hardware can stretch or snap.

Unifit Fastener supplies high tensile bolts and nuts for construction, automotive, heavy equipment, and manufacturing. Our range covers hex bolts and socket head cap screws in metric sizes M5 to M20 including M6, M8, M10, M12, M14, M16, and M20. We stock grades 8.8, 10.9, and 12.9 with black, zinc plated, and galvanised finishes for different environments.

When choosing between regular hardware and high tensile bolts, consider the forces on the joint. For structural frames, suspensions, machinery mounts, and anchor points, selecting high tensile bolts and nuts in grades 10.9 or 12.9 adds a margin of safety and keeps joints tight under vibration and impact. This makes them a dependable choice wherever a high tension bolt is required.

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High Tensile Bolts Manufacturer and High Tensile Nuts Supplier in India

A high tensile hex bolt is used where the joint sees heavy tension or pull. When two parts are clamped together, excessive tensile load can cause a standard fastener to stretch or crack. To avoid failure, these bolts are made from heat-treated alloy steel or carbon steel with higher tensile strength. For reference, a typical 304 stainless steel fastener has an ultimate tensile strength of about 515 MPa, which is adequate for general use but not for high-stress assemblies.

As a high tensile fasteners manufacturer and supplier in India, Unifit Fastener offers high tensile bolts and nuts engineered for demanding service. In applications with sustained tension, a regular bolt may fail; high tensile steel bolts resist stretch and maintain clamp load. Produced from stronger materials like heat-treated alloy or carbon steels, and select high tensile stainless steel bolts for corrosion resistance, these fasteners deliver reliable performance where strength and safety are critical.

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Standard Specification Of High Tensile Nut Bolt

Specify grade, material, thread, and finish for your high tensile nut bolt order. We supply to print with MTCs and consistent torque performance.

Grades	Grade 10.9, Grade 8.8, DIN 933 Grade 12.9
Standard	IS 1364 / IS 1363 & DIN EN ISO 4014 & 4017 DIN 931 / 933
Size	Dia M 20 to 100 mm Inch 3/4" to 3.1/2"
finish	Zinc plated / Plain / Hot dip galvanised

Different High Tensile Bolt and Nuts Types

Select the high tensile bolts and nuts type your job needs like hex, socket, flange, countersunk, coach, anchor, stud. In stock and ready to ship.

T Bolts HT Strength Fasteners M8 X 25

HT 210mm stainless steel u-bolt

High Tensile Fasteners nut and bolt, din931 Hex Bolts and Nuts

T hammer head Bolts High Tensile Strength Fasteners M8 X 25

4F3653 for Excavators high Tensile Fasteners 40Cr 5/8" Plow Bolts & Nuts

Nuts Bolts Fasteners high tensile hinge bolt

HT hex bolts shoulder nut m32 fasteners

HT M2 to M12 clamp u bolt with nut screw

High Tensile Steel Sleeve Anchor Fasteners Bolt

High tensile J hook anchor bolt

high tensile U- bolts

HT Fasteners nut and bolt

Material Properties of M10 High Tensile Studs

Choose M10 high tensile studs by grade and heat treatment for the required tensile and yield. Options in alloy steel and high tensile stainless.

Nominal Size Range	(mm)
Class 8.8	Medium carbon steel, quenched and tempered
Class 10.9	Alloy steel, quenched and tempered
Class 12.9	Alloy steel, quenched and tempered

Dimension of High Tensile Set Screw

Confirm size, pitch, and length for your high tensile set screw requirement. Tight tolerances for repeatable preload and clean assembly.

Bolts Size	A O.D.	B I.D.	C Thickness Min	C Thickness Max
1/4"	5/8	9/32	0.051	0.080
5/16"	11/16	11/32	0.051	0.080
3/8"	13/16	13/32	0.051	0.080
7/16"	59/64	15/32	0.051	0.080
1/2"	1-1/16	17.32	0.097	0.177
5/8"	1-5/16	11/16	0.122	0.177
3/4"	1-15/32	13/16	0.122	0.177
7/8"	1-3/4	15/16	0.136	0.177
1"	2	1-1/8	0.136	0.177
1-1/8"	2-1/4	1-1/4	0.136	0.177
1-1/4"	2-1/2	1-3/8	0.136	0.177
1-3/8"	2-3/4	1-1/2	0.136	0.177
1-1/2"	3	1-5/8	0.136	0.177
1-3/4"	3-3/8	1-7/8	0.178	0.28
2"	3-3/4	2-1/8	0.178	0.28
2-1/4"	4	2-3/8	0.24	0.34
2-1/2"	4-1/2	2-5/8	0.24	0.34
2-3/4"	5	2-7/8	0.24	0.34
3"	5-1/2	3-1/8	0.24	0.34
3-1/4"	6	3-3/8	0.24	0.34
3-1/2"	6-1/2	3-5/8	0.24	0.34
3-3/4"	7	3-7/8	0.24	0.34
4"	7-1/2	4-1/8	0.24	0.34

Weight of M8 High Tensile Bolt

Plan lifts, freight, and counts with accurate M8 high tensile bolt weights. Ideal for bulk procurement and site logistics.
LENGTH in Milimeter

LENGTH	M 5	M 6	M 8	M 10	M 12	M 14	M 16	M 18	M 20	M 22
16	0.448	0.743	1.590	3.211
20	0.598	0.812	1.711	3.411	4.892
25	0.660	0.897	1.871	3.660	5.252	8.170
30	0.737	1.010	2.070	3.912	5.574	9.690	10.707		18.657
35	0.804	1.120	2.271	4.223	5.974	10.000	11.416	16.026	19.608
40	0.881	1.230	2.470	4.533	6.410	10.288	12.107	16.667	20.747
45	0.958	1.340	2.671	4.840	6.859	10.504	12.821	17.241	21.739
50	1.030	1.450	2.870	5.155	7.299	11.261	13.624	17.857	22.727	28.409
55		1.560	3.071	5.464	7.740	11.628	14.409	18.868	23.810	30.120
60		1.670	3.270	5.774	8.183	12.255	15.244	20.000	25.126	32.051
65		1.781	3.472	6.083	8.621	12.626	16.026	21.008	26.455	34.014
70		1.890	3.671	6.394	9.058	12.987	16.835	22.124	27.778	35.461
75		2.000	3.873	6.702	9.506	13.228	17.606	23.256	29.070	39.063
80		2.111	4.072	7.013	10.000	13.889	18.248	24.510	30.303	40.000
90			4.472	7.634	10.917	14.925	19.841	26.042	33.113	41.667
100			4.873	8.251	11.820	16.340	21.459	27.778	35.714	46.296
110				8.881	12.723	17.730	23.041	31.250	38.168	47.170
120				9.506	13.624	18.797	24.631	32.895	40.984	50.000
130				10.101	14.535	20.000	26.316	34.722	43.478	52.632
140				10.707	15.432	20.833	27.933	35.461	46.296	55.556
150				11.312	16.340	22.222	29.412	37.594	48.544	58.824
160				11.905	17.241	24.272	31.056	40.984	50.505	61.728
170				12.500	18.116		32.680		53.191	64.935
180				13.123	19.011	26.882	34.247		55.556	67.568
190				13.736	19.920		35.971		58.140	70.423
200				14.327	20.833	29.586	37.594	49.020	60.976	73.529
220				15.528	22.624		40.650		65.789	79.365
240				16.722	24.510		43.860		71.429	84.746
250				17.301	25.381		45.455		74.627	87.719
260				17.921	26.316		47.170		76.923	90.909
280				19.157	28.090		50.505		81.967	98.039
300				20.325	29.940		53.763		87.719	104.167
320					31.646		56.818		92.593
340					33.557		60.241		98.039
360					35.211		63.291		104.167
380					37.037		66.667		108.696
400					39.063		69.444		113.636

Sizes of High Tensile Steel Threaded Rod

Order high tensile steel threaded rod in standard diameters and cut lengths. Straightness and thread quality checked for easy fit-up.

High Tensile Fasteners Type	SIZE	GRADE	ASME	ISO	ASTM
ASTM F568 Socket Head Cap Fasteners	M1.6 to M64	12.9	B18.3.1 M	4762	A574M
Socket Low Head Cap Fasteners	M4 to M20	10.9
ASTM F568 Socket Head Shoulder Fasteners	M6 to M24	012.9	B18.3.3M
Countersunk Socket Head Fasteners	M3 to M20	012.9	B18.3.5M	10642	F835M
ASME SF568 Button Head Socket Fasteners	M3 to M12	012.9	B18.3.4M	7380	F835M
Flange Button Head Socket Fasteners	M3 to M10	012.9			F835M
HT Knurled Point Socket Set Fasteners	M3 to M20	45H	B18.3.6M	4029	F912M
Flat Point Socket Set Fasteners	M6 to M12	45H	B18.3.6M	4026	F912M
Dog Point Socket Set Fasteners	M3 to M20	45H	B18.3.6M	4028	F912M
Cone Point Socket Set Fasteners	M3 to M12	45H	B18.3.6M	4027	F912M
HT Plain Point Socket Set Fasteners	M3 to M20	45H	B18.3.6M	4029	F912M
Taper Pressure Plug	M8 to M22	-

High Tensile Fasteners Type	SIZE	PROPERTY CLASS	TENSILE STRENGTH	STANDARD
Hex Head Fasteners	M4 to M80	10.9	1040N / mm2 min	ISO 4017 (Full Thread) ISO 4014 (Half Thread)

High Tensile Nuts Type	SIZE	PROPERTY CLASS	STANDARD
M10 HT Hex Nut	M6 to M42	10	ISO 4032
HT Nylock Nut	M6 to M20 (Gr.8) M10 to M24 (Gr.10)	8 & `10	DIN 982
M8 HT Nylock Nut	M6 to M20 (Gr.8) M10 to M24 (Gr.10)	8 & 10	DIN 985
HT Hex Weld Nut	M6 to M12	8	DIN 929

High Tensile Washers Type	SIZE	HARDNESS	STANDARD
Square Section Spring Washer, High Tensile	3mm to 39mm	HV (430 to 530)	DIN 7980
Flat Section Spring Washer, High Tensile	3mm to 39mm	HV (430 to 530)	DIN 127 B
Hardened Washer, High Tensile	12mm to 30mm	HV (300 to 370)	IS 2016
Hardened Steel Washer, High Tensile	12mm to 56mm	Rockwell 26 to 45 (HDG) Rockwell 38 to 45 (Coated)	ASTM F436M

High Tensile Bolt Temperature (RP0.2 N/mm²)

Match service temperature to high tensile bolt RP0.2 values. Maintain preload and safety margins in hot running equipment.

High Tensile Class	100°C	200°C	250°C	300°C
Grade 5.6 Bolts	270	230	215	195
Garde 8.8 Bolts	590	540	510	480
Grade 10.9 Bolts	875	790	745	705
Grade 12.9 Bolts	1020	925	875	825

Comparison: High Tensile Nut Vs Normal Nut

Pair the right high tensile nut with your bolt grade for proof load and torque retention. Avoid mixed hardware and premature loosening.

Feature	High Tensile Nut	Normal Nut
Material	Stainless and Alloy Steel	Standard Alloys
Applications	High Stress Environments	Light Duty Applications
Tensile Strength	Higher 800 MPa	below 500 MPa

Testing Methods of High Tensile Fasteners

Supply includes testing as required for high tensile fasteners. Tension, hardness, torque-tension, impact, and torsion available on request.

Test Methods	High Tensile Fasteners Types
Torsion Test	All Screws Except Waisted Shank Screws
Charpy Impact Test	Bolts, screws and studs with a diameter ≥ 16 mm
Hardness Testing	All Bolts and Screws
Decarburization and Retempering Test	Class 8.8 to 12.9
Proof Load Test	Finished bolts, Screws and Studs
Head Soundness Test	Screws and Bolts
Proof Load Test	Finished bolts, studs and screws
Proof Load Test	Finished bolts, Screws and Studs

High Tensile Fasteners & Bolts Grade 8.8 & 10.9, 12.9: Recommended Tightening Torques

Use these torque values for grade 8.8, 10.9, 12.9 to set correct preload. Supports reliable clamping and longer service life.

Size	Grade 8.8	Grade 10.9	Grade 12.9
-	Tightening Torque (Nm) Maximum	Tightening Torque (Nm) Maximum	Tightening Torque (Nm) Maximum
M2	Enquire	Enquire	Enquire
M3	1.37	1.37	1.37
M4	3.1	3.1	3.1
M5	6.15	6.15	6.15
M6	10.5	10.5	10.5
M8	26	26	26
M10	51	51	51
M12	89	89	89
M14	141	141	141
M16	215	215	215
M18	295	295	295
M20	420	420	420

High Tensile Bolt Load Capacity

Verify design limits with the high tensile bolt load table. Select size and grade to meet factor of safety and code needs.

Size	Grade 12.9	Grade 8.8	Grade 10.9
M3	6,140	4,020	5,230
M4	10,700	7,020	9,130
M6	24,500	16,100	20,900
M8	44,600	29,200	38,100
M10	70,800	46,400	60,300
M12	103,000	67,400	87,700
M14	140,000	92,000	120,000
M16	192,000	125,000	163,000
M18	234,000	159,000	200,000
M20	299,000	203,000	255,000
M22	370,000	252,000	315,000
M24	431,000	293,000	367,000
M30	684,000	466,000	583,000
M36	997,000	678,000	850,000

High Tensile Fasteners Price List

Get current pricing for high tensile fasteners by size, grade, and finish.

High Tensile Fasteners Price List	Price Per Pcs.
High Tensile Machine bolts price	USD $5.12
M10 HTHex head bolts price	USD $5.0
ASTM F568 HT Socket Head Cap Screw price	USD $3.60
HT Screws price	USD $4.70
M8 High Tensile Dowel Pins price	USD $2.20

Frequently Asked Questions About High Tensile Fasteners

What are the grades of high tensile fasteners?

The main grades are 8.8, 10.9, and 12.9—higher numbers mean greater tensile strength, with 8.8 for structural use, 10.9 for automotive, and 12.9 for high-performance.

How to identify HT bolt?

HT bolts have grade markings on the head (e.g., 8.8, 10.9, 12.9), a fine thread pitch, and may feature color codes like yellow for Grade 12.9; always confirm with head markings

What's the best coating for high tensile bolts?

The best coatings are zinc/aluminum-based (like Geomet), PTFE, or zinc-rich coatings for corrosion resistance; avoid electroplating on bolts above 150 ksi

What is the standard size for high tensile bolts?

Standard sizes range from M6 to M36 diameter, with lengths and thread types available as per ISO, DIN, or customer specifications.