Related Resources: hardware

### Typical Elongation Common Bolting Materials

Bolt & Screw Torque Charts and Equations

Typical Elongation Chart for Common Bolting Materials

Indicated elongation figures (in thousandths of an inch) are for various percentages of yield strengths (y.s.) of different bolts with a 1 in. grip length. (Modulus of elasticity assumed to be 30 x 106 psi unless otherwise noted.) To obtain desired elongation for a particular metal, read the elongation figure under the appropriate percentage of yield and multiply by the grip length in inches. For example, to obtain the expected elongation for an SAE Grade 5 bolt stretched to 80% of yield, with a 5 in. grip length, select the appropriate figure, which in this case is 2.6, and multiply by 5. The answer is 0.013 in.

Note and warning: Many factors determine the ‘‘correct’’ stretch for a given fastener and application. Use this table with caution.

 Bolting Material 20% of Yield 40% of Yield 60% of Yield 80% of Yield 100% of Yield Monel 40 K psi y.s. 0.3 0.5 0.8 1.1 1.3 SAE GR 2 55 K psi y.s. 0.4 0.7 1.1 1.5 1.8 SAE Grade 3; B7 and B16 over 4 in. diameter 80 K psi y.s. 0.5 1.1 1.6 2.1 2.7 SAE Grade 5; A325; B7 and B16 up to 4 in. diameter 96 K psi y.s. 0.6 1.3 1.9 2.6 3.2 SAE Grade 8; A490 120 K psi y.s. 0.8 1.6 2.4 3.2 4.0 Inconel 718 180 K psi y.s. 1.2 2.4 3.6 4.9 4340 steel, RC47 200 K psi y.s. 1.3 2.7 4.0 5.3 6.6 Best available high-bolt material 240 K psi y.s. 1.6 3.2 4.8 6.4 8.0 Titanium (6A14V) 134 K psi y.s. E = 17 x 106 1.6 3.2 4.8 6.4 8.0

Related:

Reference:

Courtesy of Raymond Engineering Inc., Middletown, CT.