Difference between fastener standard for bolts IS1367Gr. 4.6, 8.8 - WELDING AND NDT TIPS STATIC PIPING TRICKS PODCAST ARAMCO INSPECTOR WELDING - NON DESTRUCTIVE TEST

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Difference between fastener standard for bolts IS1367Gr. 4.6, 8.8

 This is fastener standard for bolts:

Grade 8.8 means, Approx. 800 Mpa tensile strength and 640 MPa yield strength (you will arrive at the YS by multiplying both the numbers times 10. That is 8x8x10=640)

Similarly, 10.9 means approx.1000Mpa TS and 900 Mpa yield strength. See the below-given details.

The grade 8.8 refers to the tensile strength which is generally 116,000 psi, grade 10.9 is generally 150,000 and grade 12.9 is generally 175,000 psi. Grade 8.8 high tensile steel is often referred to as the structural grade for bolts.

Material Property Class Tensile Strength, Mpa Hardness Heat Treatment Tempering
Low or medium carbon steel with max limits for C 0.55, P0.048, S0.058 4.6 400 B67-B87 No
Low or medium carbon steel with max limits for C 0.55, P0.048, S0.058 4.8 420 B71-B87 No
Low or medium carbon steel with max limits for C 0.55, P0.048, S0.058 5.8 520 B82-B95 No
Medium carbon steel with max   limits for C0.28- 0.55, P0.048, S0.058 8.8 830 C23-C34 Oil Quenched min 425°C
Medium carbon steel with max   limits for C0.28- 0.55, P0.048, S0.058 9.8 900 C27-C36 Oil Quenched min 410°C
Medium carbon steel with max   limits for C0.28- 0.55, P0.048, S0.058 10.9 1040 C33-C39 Oil Quenched min425°C
Medium carbon steel with max   limits for C0.31- 0.65, P 0.045 MAX, S 0.045MAX 12.9 1220 C38-C44 Oil Quenched min 380°C

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