Strong Match — 91.4% match
based on chemical composition and mechanical property overlap.
BS 970 (Part 1) 708M40 (BS 970 (Part 1):1991) and BS 970 (Part 1) 709M40 (BS 970 (Part 1):1991) are both steel grades.
Both fall under the Alloy Steel category.
BS 970 (Part 1) 708M40 is typically used for used for axles, gears, shafts, studs, crankshafts, and heavy-duty machinery parts., while BS 970 (Part 1) 709M40 is commonly used for used for aircraft parts, heavy-duty gears, transmission shafts, connecting rods, crankshafts, and engineering fasteners..
BS 970 (Part 1) 708M40 is defined under British Standards (BS), originating from United Kingdom, while BS 970 (Part 1) 709M40 is defined under British Standards (BS), originating from United Kingdom.
As per chemical composition, BS 970 (Part 1) 708M40 vs BS 970 (Part 1) 709M40 is a 91.4% match.
Mechanical property data is not available for both grades, so this factor could not be scored.
Combined, this makes them a strong match overall at 91.4%.
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Typical Applications
BS 970 (Part 1) 708M40
Used for axles, gears, shafts, studs, crankshafts, and heavy-duty machinery parts.
BS 970 (Part 1) 709M40
Used for aircraft parts, heavy-duty gears, transmission shafts, connecting rods, crankshafts, and engineering fasteners.
Can BS 970 (Part 1) 708M40 Be Substituted With BS 970 (Part 1) 709M40?
BS 970 (Part 1) 708M40 and BS 970 (Part 1) 709M40 overlap closely enough on chemistry and mechanical properties that BS 970 (Part 1) 709M40 is often considered as a substitute for BS 970 (Part 1) 708M40 in many applications. Always confirm the specific property range your application needs before substituting, and check with your supplier's mill certificate.
What is the difference between BS 970 (Part 1) 708M40 and BS 970 (Part 1) 709M40?
Both grades share a similar composition profile; see the specification table above for the exact chemistry and mechanical property values.
Can BS 970 (Part 1) 708M40 be substituted with BS 970 (Part 1) 709M40?
BS 970 (Part 1) 708M40 and BS 970 (Part 1) 709M40 overlap closely enough on chemistry and mechanical properties that BS 970 (Part 1) 709M40 is often considered as a substitute for BS 970 (Part 1) 708M40 in many applications. Always confirm the specific property range your application needs before substituting, and check with your supplier's mill certificate.