Aircraft Steel BS S106 / 4S106D (MSRR 6001)

Technical Data Sheet


Chemical Composition Limits
Weight% C Si Mn P+S max Cr Mo Ni Sn
3S106 0.20-0.28 0.10-0.35 0.40-0.70 0.020 3.00-3.50 0.45-0.65 0.30 max 0.030 max
4S106 0.20-0.28 0.10-0.35 0.40-0.70 0.020 3.00-3.50 0.50-0.70 0.30 max 0.030 max
Chemically similar British Specifications BS.970 Pt2
Weight% C Si Mn P+S max Cr Mo Ni -
722M24 0.20-0.28 0.10-0.35 0.45-0.70 0.025 3.00-3.50 0.45-0.65 - -
EN40B 0.20-0.30 0.10-0.35 0.40-0.65 0.050 2.90-3.50 0.40-0.70 0.40 max -
Other Chemically similar Specifications
Weight% C Si Mn P+S max Cr Mo Ni Sn
WS 1.7365 0.25-0.30 0.15-0.25 0.60-0.80 0.035 max 3.00-3.30 0.45-0.550 - -

BS s106 is the British aerospace equivalent of 722M24 / EN40B. It is a medium strength 3% Chrome-Moly nitriding steel that develops high hardness after heat treatment, and is used in both aerospace applications and motorsports industries. It is generally supplied as bright bar in the hardened, tempered and stress relieved condition, designated S106D. It can also be supplied to the Rolls Royce specification MSRR 6001.

Typical Mechanical Properties


Grade Treatment Tensile Strength Rm N/mm² Proof Stress Rp 0.2, N/mm² Elongation in 5.65 √Cross Sectional Area% Hardness HB Ruling Section
S106 Solution Annealed - - - 269 max -
S106D Hardened and Tempered 930/1080 740 35 269/321 6"

Alloy S106 is available in Bar . For all stock availability contact Sales.

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Every effort is made to ensure that technical specifications are accurate. However, technical specifications included herein should be used as a guideline only. All specifications are subject to change without notice.