Post Stock Login Register

UNI 7846 18CrMo4 vs BS 970 (Part 1) 708M20

Close Alternative — 84.3% match based on chemical composition and mechanical property overlap.

UNI 7846 18CrMo4 (UNI 7846:1978) and BS 970 (Part 1) 708M20 (BS 970 (Part 1):1983) are both steel grades. Both fall under the Alloy Steel category. UNI 7846 18CrMo4 is typically used for used in gears, shafts, pinions, crankshafts, axles, and heavy machinery components., while BS 970 (Part 1) 708M20 is commonly used for case hardening steel for mechanical and allied engineering purposes (table 11 mechanical properties).. UNI 7846 18CrMo4 is defined under Ente Nazionale Italiano di Unificazione (UNI), originating from Italy, while BS 970 (Part 1) 708M20 is defined under British Standards (BS), originating from United Kingdom.

As per chemical composition, UNI 7846 18CrMo4 vs BS 970 (Part 1) 708M20 is a 84.3% match. Mechanical property data is not available for both grades, so this factor could not be scored. Combined, this makes them a close alternative overall at 84.3%.

Frequently Compared With UNI 7846 18CrMo4:
GB/T 3077 12Cr2Ni4A UNI 11234 100Cr6 NF A35-565 100C6 GOST 4543 12HN3A IS 4367 07Cr4Mo6 IS 1570 (Part 4) 103Cr6 IS 1570 (Part 4) 105Cr5 IS 4367 10Cr9Mo10 IS 1570 (Part 4) 103Cr4 IS 1570 (Part 7) 10Cr36Mo10H IS 1570 (Part 4) 07Cr4Mo6 IS 1570 (Part 4) 10Cr20Mo6
Match Breakdown
CHEMISTRY MATCH
84.3%
MECHANICAL MATCH
No shared data
OVERALL
84.3%
Specifications
Property UNI 7846 18CrMo4 BS 970 (Part 1) 708M20
Standard UNI 7846:1978 BS 970 (Part 1):1983
Category Alloy Steel Alloy Steel
C (%) 0.15-0.21 0.17-0.23
Si (%) 0.15-0.40 Not specified
Mn (%) 0.60-0.90 0.60-0.90
Cr (%) 0.90-1.20 0.85-1.15
Mo (%) 0.15-0.30 0.15-0.25
P (%) 0.035 max <=0.035
S (%) 0.035 max <=0.040
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Mechanical Properties
Property UNI 7846 18CrMo4 BS 970 (Part 1) 708M20
Tensile Strength 700-900 MPa Not specified
Yield Strength 540 MPa min Not specified
Elongation 14% min Not specified
Hardness 200-260 HB Not specified
Typical Applications
UNI 7846 18CrMo4
Used in gears, shafts, pinions, crankshafts, axles, and heavy machinery components.
BS 970 (Part 1) 708M20
Case hardening steel for mechanical and allied engineering purposes (Table 11 mechanical properties).
Key Differences
Can UNI 7846 18CrMo4 Be Substituted With BS 970 (Part 1) 708M20?
UNI 7846 18CrMo4 and BS 970 (Part 1) 708M20 are a close alternative rather than a direct substitute. Some properties overlap well, but check the specific chemistry and mechanical rows above against your application's requirements before treating them as interchangeable.
Forms & Sizes Available on M-EX
UNI 7846 18CrMo4
Round Bar → (2 listings)
Diameter: 50–50 mm (1.97–1.97 in)
Length: 5200–5400 mm (204.72–212.6 in)
BS 970 (Part 1) 708M20
No active listings currently.
On M-EX Right Now
UNI 7846 18CrMo4
2 active listings and RFQs →
BS 970 (Part 1) 708M20
0 active listings and RFQs →
Frequently Asked Questions
What is the difference between UNI 7846 18CrMo4 and BS 970 (Part 1) 708M20?
UNI 7846 18CrMo4 specifies Si which is not specified for BS 970 (Part 1) 708M20.
Can UNI 7846 18CrMo4 be substituted with BS 970 (Part 1) 708M20?
UNI 7846 18CrMo4 and BS 970 (Part 1) 708M20 are a close alternative rather than a direct substitute. Some properties overlap well, but check the specific chemistry and mechanical rows above against your application's requirements before treating them as interchangeable.