45MNBH

Official GB/T5216-2014, cover PDF1, Clause 6.1 PDF7, Table 1 and footnotes PDF8/9; Heat-analysis mass fractions wt%. ; Clause 6.1.2 residual Cu≤.25, Cr≤.30, Ni≤.30%; Specified alloy ranges in the table shall take priority; Hot working Cu≤.20 separate condition. ; 6.1.3 O≤.0020%; Unspecified residual limits such as Mo must not be assumed zero. ; Note a: Only for 16CrMnH/20CrMnH/25CrH/28CrH, Si≤.12% may be agreed at the buyer's request; the effect on mechanical properties must be considered.. ; Note b: Per buyer's request, S may be .015–.035%; in this case, the finished product tolerance is ±.005%, which is not a default heat analysis relaxation. ; H/HH/HL are different hardenability bands; S denotes a sulfur-related grade-designation condition.; Only compositions of H grades are listed this time; hardenability curves and all mechanical properties are not claimed to have been verified. ; The intended use for metal forming or machining under this standard must be stated in the contract.; Cold heading, annealing and actual wire-rod supply require separate confirmation; do not automatically add products..

GB/T 5216—2004 original Tables 1/2 and 6.1, ladle-analysis mass fraction wt%; retain the actual 2004 edition.

For high-quality steel, Note a to Table 1 adds A before H (e.g. 40CrAH); P/S by quality level and residual Cu/Cr/Ni follow Table 2; do not mix with the 2014 edition.

Under 6.1.3, Cu≤0.20% for hot-pressure processing. If the purchaser requires S 0.020–0.035%, add S before H; the sulfur tolerance ±0.005 is separately stated and does not expand the default range.

Table 1 alloy-element ranges take precedence over Table 2 residual limits; a blank means unspecified, not zero.

H/HH/HL hardenability bands, delivery condition, hardness and suitability for cold-heading processes require separate verification; this does not automatically create a supply product.