Grade 8 vs 10.9 High Tensile bolts

CARBON STEEL BOLTING PROPERTY CLASSES 8.8 10.9 12.9 & 14.9

CLASSES 8.8 10.9 12.9 & 14.9 grade are stipulated in various international standards including DIN 267 and ISO 898. The symbol for the property classes of hex bolts, screws and studs consists of two numbers separated by a decimal point. 8.8, 10.9, 12.9, 14.9 etc.

Grade 8 vs 10.9

Hex bolts, stud bolt, threaded rod and screws property classes is consists of two numbers which can be separated by a decimal point such as 8.8, 10.9, 12.9, and 14.9. To calculate the nominal tensile strength multiply the whole number before the decimal point by a hundred in newtons per millimeter squared.

Difference Between

Grade 8 bolt

Gr 8 bolt capability in yield (stretch) = 130,000 lbs / in2 x .03349 in2 = 4354 lbs minimum
High tensile Grade 8 bolt capability in tension (failure) = 150,000 lbs / in2 x .03349 in2 = 5024 lbs minimum
Grade 8 hex bolts have 6 marks on the head.
tensile strength is 150,000 lbs per square inch
ultimate shear strength

Grade 5 bolt

Gr 5 Hex bolt capability in yield (stretch) = 92,000 lbs / in2 x .03349 in2 = 3081 lbs minimum
Grade 5 hex bolt capability in tension (failure) = 120,000 lbs / in2 x .03349 in2 = 4019 lbs minimum

Grade 10.9 bolt

HT bolts Grade 10.9 are manufactured using medium carbon steel, medium carbon steel alloy and low carbon boron steel that has been quenched and tempered. 
din 6914 grade 10.9 bolts meet ASTM A324 grade BD and SAE J429,
metric grade 10.9 bolts in a wide range of standard, coarse and fine sizes

Due to space and time limitations, here is a chart showing you the tension and shear minimum capabilities of different grade fasteners relative to their size.

Capabilities of different grade fasteners

Internationally, mechanical stress is expressed in newtons per square area, in bolting N/mm2. Common practise overseas is to use the unit megapascal (MPa), which corresponds directly to N/mm2.
For example 1,200 N/mm2 = 1,200 MPa

An example using a hex bolt with property class 10.9

  • The Nominal tensile strength of a 10.9 bolt is calculated
    10 x 100 = 1,000 N/mm2 (MPa)
  • The Yield stress ratio 9 x 10 = 90%
  • The Yield stress is therefore
    90% of 1,000 = 900 N/mm2 (MPa)

Bolts and Studs can be supplied in Property classes

Grade 3.6 Grade 4.6
Grade 4.8 Grade 5.6
Grade 5.8 Grade 6.8
Grade 8.8 Grade 9.8
Grade 10.9 Grade 12.9
Grade 14.9  

Nuts Property classes

Grade 6 Grade 8
Grade 9 Grade 10
Grade 12 Grade 14

Nuts of a higher property class can nomally be used in the place of nuts of a lower property class.

* Property classes 14.9 are not detailed in the ISO or ANSI standards.

Grade 8 Specification

Grade 8 Bolt Type Anchor Bolt, Carriage Bolt, Flange Bolt, Hanger Bolt, Hexagon Bolt / Tap Bolt, Lag Bolt, Machine Bolt, Plow Bolt, Shoulder Bolt, Square Head Bolt, Stud Bolt, T-Head Bolt, Toggle Bolt, U-Bolt
Inch #0000 -3" (customized sizes available)
Metric M1.6 - M48
Length Customized Length
Grade Non Ferrous, Grade 12.9, 10.9, 9.8, 8.8, 5.8, 4.6, B7, 2, 5, 8, L9
Material Brass, Bronze / Copper Base Alloy, Copper, Molybdenum, Steel, Hardened Steel, Stainless Steel, Superalloy (Inconel, Hastelloy, Monel), Titanium, Exotic Metals, Other
Method Cold forming, Hot Forging, Wire Forming
Fastener Standards ASME / ANSI, BS, DIN, ISO, JIS, SAE, Other
Application Industries & uses Agriculture, Automotive, Construction and Infrastructure, Energy, Transportation
Testing Methods ASTM E38, E76 and E354, ASTM E53, E54, E62, E75and E478, ASTM E34, E101 and E227, ASTM E 120 and E1409.
Threads Configuration ASME B1.1 2A/3A – 2B/3B Inch Unified Threads and B1.13M 6h-6G Metric Coarse Threads
Thread Diameters M6 to M36
Certification Dual Certified As per ASTM & ASME Codes

Grade 8 Material Stock

Grade 8 Bolts supplier
  • Hex Head Bolts
  • Wing Bolts
  • Eye Bolts
  • Allen Key Bolts
  • J Bolts
  • Countersunk Bolts
  • Stud Bolts
  • Flange Head Bolts
  • Anchor Bolts
  • Roofing Bolts
  • Torx Bolts
  • Screw Thread Eye Bolt
  • Deck Bolts
  • Round Head Bolts
  • Carriage Bolts
  • Tap bolts
  • Lag Bolts
  • U Bolts
  • Hex Bolts
  • T-head bolt
  • Forged Hook Bolts
  • Toggle bolt
  • Machine bolts
  • Hanger Bolts
  • Socket Button Head Bolts
Grade 8 Bolts Manufacturer
  • Eye Bolt With Shoulder
  • Eye Bolt No Shoulder
  • Square Head Bolts
  • Turned Eye Bolts
  • Square U-bolts
  • Long Bolt
  • Serrated Flange Bolts
  • Shoulder bolt
  • Heavy Hex Bolts
  • Hex Flange Bolts
  • 12-Point Flange Bolts
  • Button Head Bolts
  • Jack Bolts
  • Bent Bolts
  • Allen Bolt
  • 12-Point Flange Bolts
  • Carriage Bolts
  • Elevator Bolts
  • Hanger Bolts
  • Hex Machine Bolts
  • Timber Bolts
  • Sex bolts
  • Hexagon Bolts for Steel Structures
  • Step Bolts for Steel Structures
Grade 8 Bolts Stockist
  • Hex Tap Bolts
  • Hexagon Head Bolts
  • Tee-Hammer Head Bolt
  • Security Anti Theft Bolts
  • Structural Bolts
  • Hex Flange Bolt
  • Metric Bolts
  • Plow Bolts
  • Square Head Machine Bolts
  • Step Bolts
  • Hex Head Bolts
  • Hex Head Bolt With Plain Spring Washer
  • Hexagon Head Bolts ISO 4014
  • Hexagon Flange Bolts DIN 6921
  • Hexagon Head Bolts ISO 4016
  • DIN 976-1 Stud bolts
  • High Strength Structural Bolts

The Metric System

Product Type Metric Specification Scope
Din ISO ANSI/ASME
HCS 931 4014 B18.2.3.1M Partially Threaded
933 4017 Fully Threaded
960 8676 Partially Threaded (Fine)
961 8765 Partially Threaded (Fine)
Hex Nuts 934 4032 B18.2.4.1M (style 1) Classes 6, 8, & 10
SHCS 912 4762 B18.3.1  
BHSHCS N/A 7380 B18.3.4M  
FHSCS N/A 7991 B18.3.5  

Metric Stainless Steel Fasteners

Steel Composition Alloy Group Property Class
  # Steel Type # Minimum Tensile Strength in MPa1
A Austenitic 1 18-82 50 500 (soft)
2 18-83 70 700 (cold-worked)
4 316 80 800 (high strength)
F Ferritic 1 430 45 450 (soft)
60 600 (cold-worked)
C Martensitic 1 410 50 500 (soft)
4 416,416Se 70 700 (hardened and tempered)
    1104 1100 (hardened and tempered)
3 431 80 800 (hardened and tempered)
    1205 1200 (hardened and tempered)
P6 Precipitation-Hardening 1 630 (17/4) 90 900
  • 1 If it is a stainless nut, then this number will indicate the Nut Proof Stress rather than the Minimum Tensile Strength.
  • 2 Specifics vary based on specification used. ISO alloy group 1 for austenitic indicates 18-8 with sulfur added for machining. ASTM alloy group 1 austenitic may indicate 304, 304L, 305, 384, or XM7. At customer request, 303, 303Se, or XM1 may be used.
  • 3 Specifics vary based on specification used. ISO alloy group 2 for austenitic indicates 18-8. ASTM alloy group 2 austenitic will consist of 321 or 347.
  • 4 C1-110 & C4-110 apply to ASTM metric only.
  • 5 C3-120 applies to ASTM metric only.
  • 6 Precipitation-Hardening stainless steel applies to ASTM metric only.

Mechanical Properties

Property 3.6 4.6 4.8 5.6 5.8 6.8 8.8 10.9 12.9
<= 16mm > 16mm

Tensile Strength
Rm in MPa (N/mm2)

 nominal value 300 400 400 500 500 600 800 800 1000 1200
minimum 330 400 420 500 520 600 800 830 1040 1220
Vickers Hardness
HV=F 98N		 minimum 95 120 130 155 160 190 230 255 310 372
maximum 220 220 220 220 220 250 300 336 382 434
Brinell Hardness
HB F=30D2		 minimum 90 114 124 147 152 181 219 242 295 353
maximum 209 238 285 319 363 412
Rockwell Hardness HR minimum HRB 52 67 71 79 82 89
minimum HRC 20 23 31 38
maximum HRB 95 95 95 95 95
maximum HRC 30 34 39 44
Surface Hardness
HV 0.3		 maximum 320 356 402 454
Yield Stress
Rel in MPa(N/mm2)		 nominal value 180 240 320 300 400 480
minimum 190 240 340 300 420 480
0.2% elongation limit
Rp0.2
in Mpa (N/mm2)		 nominal value 640 640 900 1080
minimum 640 660 940 1100
Test stress Sp Sp/ReL or Rp0.2 0.94 0.94 0.91 0.94 0.91 0.91 0.91 0.91 0.88 0.88
MPA (N/mm2) 180 225 310 280 380 440 580 600 830 970
Elongation after fracture
A5 in %		 minimum 25 22 14 20 10 8 12 12 9 8
Minimum notch impact energy in Joules 25 30 30 20 15
Head Impact Toughness No Fracture
Maximum Height of the Thread Zone Not
Decarburized E		 1/2H1 1/2H1 2/3H1 3/4H1
Maximum Depth of Decarburization Gmm .015 .015 .015 .015

Mechanical Properties for Socket Products

DIN 912 Socket Cap Screws

Property Class 12.9
Hardness (HRC) 39-44
Tensile Strength (Mpa) 1,220 min.
Yield Strength at 0.2% Offset (Mpa) 1,100 min.
Elongation (%) 8 min.
DIN 7984 Low Head Socket Caps
Property Class 10.9
Hardness (HRC) 32-39
Tensile Strength (Mpa) 832 min.
DIN 7991 Flat Head Countersunk Socket Cap Screws
Property Class 10.9
Hardness (HRC) 32-39
Tensile Strength (Mpa) 835 min.
ISO 7380 Button Head Socket Cap Screws
Property Class 10.9
Hardness (HRC) 32-39
Tensile Strength (Mpa) 835 min.
ISO 7379 Socket Shoulder Screws
Property Class 12.9
Hardness (HRC) 39-44
Tensile Strength (Mpa) 1,100 min.
DIN 916 Set Screws
Property Class 45H
Hardness (HRC) 45-53
ASME B18.3 Socket Cap Screws
Diameter d d <= 1/2 d > 1/2
Hardness (HRC) 39-44 37-44
Tensile Strength (psi) 145,000 min. 135,000 min.

ASME B18.3 Low Head Socket Caps

Diameter d d <= 1/2 d > 1/2
Hardness (HRC) 39-45 37-45
Tensile Strength (psi) 180,000 min. 170,000 min.
Yield Strength at 0.2% Offset (psi) 153,000 min. 153,000 min.
Elongation (%) 10 min. 10 min.

ASME B18.3 Flat Head Countersunk Socket Cap Screws

Diameter d d <= 1/2 d > 1/2
Hardness (HRC) 39-44 37-44
Tensile Strength (psi) 145,000 min. 135,000 min.

ASME B18.3 Button Head Socket Cap Screws

Diameter d d <= 1/2 d > 1/2
Hardness (HRC) 39-44 37-44
Tensile Strength (psi) 145,000 min. 135,000 min.

ASME B18.3 Socket Shoulder Screws

Hardness (HRC) 39-43
Tensile Strength (psi) 140,000 min.

ASME B18.3 Set Screws

Property Class 45H
Hardness (HRC) 45-53

Mechanical Properties for Hex Products

ISO 4014 / 4017 Hex Head Bolts

Property Class 10.9 12.9
Hardness (HRC) 32-39 39-44
Tensile Strength (Mpa) 1,040 min. 1,220 min.
Yield Strength at 0.2% Offset (Mpa) 940 min. 1,100 min.
Elongation (%) 9 min. 8 min.

ISO 4162 Hexagon Flange Bolts

Property Class 10.9 12.9
Hardness (HRC) 32-39 39-44
Tensile Strength (Mpa) 1,040 min. 1,220 min.
Yield Strength at 0.2% Offset (Mpa) 940 min. 1,100 min.
Elongation (%) 9 min. 8 min.

ASME B18.2.1 Hexagon Head Cap Screws

Property Class SAE J429-Grade 8
Hardness (HRC) 33-39
Surface Hardness (30N) 58.6 max.
Tensile Strength (psi) 150,000 min.
Yield Strength at 0.2% Offset (psi) 130,000 min.
Elongation (%) 12 min.

IFI-111 Hexagon Flange Screws

Property Class SAE J429-Grade 8
Hardness (HRC) 33-39
Surface Hardness (30N) 58.6 max.
Tensile Strength (psi) 150,000 min.
Yield Strength at 0.2% Offset (psi) 130,000 min.
Elongation (%) 12 min.
*All information is strictly informative

Grade 8 Bolts stockist in India- ASME, DIN, AS, BS

Grade 8 Bolts Coatings and plating as well as plain finished oil and tempered is available as required by the end user such as Zinc plating, Cadmium plating, Xylan ® coating, Dupont Teflon ® coating, Hot Dip Galvanized coating, Auge Antifrix ® coating, Sermagard ® coating and Niwat 1000 ® plating.

Available standard: DIN 934, ISO 4033, ISO 4032, DIN 935,DIN 936, ASME B18.2.2, ASME B18.2.4.6M, DIN 976, DIN 975, DIN 2510, DIN 939, DIN 940, DIN 938

Teflon coated bolts

PTFE coated bolts

Specialized in Aircraft Materials & Aerospace Materials