ML15MNB

Mass percent, heat analysis, GB/T28906-2025 Table 4. ; 7.1.5 residual Cr/Ni/Cu are each ≤0.20% and Sn≤0.06%; tabulated alloy Cr is not subject to the residual maximum; 7.1.7 product-analysis tolerances follow GB/T222 and must not be directly treated as heat-analysis limits. ; The standard scope for hot-rolled cold-heading wire rod does not replace confirmation of actual supply dimensions and the component manufacturing process; Mechanical properties require separate verification. ; When measuring acid-soluble aluminum, Als0.015–0.055% is used and is retained separately from total aluminum Alt0.020–0.060%; The Al element field must be interpreted with the selected measurement condition. ; Table 4 Note a: A Si lower limit below 0.10% may be negotiated and specified in the contract; do not fill in without agreement. ; Note b: When hardenability and mechanical properties meet requirements and upon mutual agreement, the lower limit of B may be relaxed to 0.0005%; Default 0.0008%. ; Note c: The Ti/N ratio may be agreed upon, but as no uniform value is provided in the original text, it shall not be automatically set or declared as satisfied. ; Note e: Cr may be added by agreement for the first 15 grades, with the addition amount to be confirmed by both parties.

GB/T28906-2012, Table 4, heat analysis, mass percent. ; Alt in the table is total aluminum, with requirement ≥0.020% but no maximum; the 2025 maximum or acid-soluble-aluminum replacement conditions are not applied. ; 6.1.5 residual Cr/Ni/Cu are each ≤0.20%; Where Cr is a tabulated alloy range, the residual Cr maximum does not apply; Where Sn is unspecified in the original text, the Sn maximum from a newer edition is not inserted. ; 6.1.7 composition tolerances follow GB/T222; Heat-analysis limits are not treated as product-analysis tolerances. ; The standard scope covers hot-rolled cold-heading wire rod; supply conditions and the actual component process still require confirmation. ; Table 4 of 2012 does not list the relaxed B minimum or low-Si agreement in edition 2025; these conditions are not applied across editions.

GB/T6478-2015, Table 4, heat-analysis mass percentages. ; 6.1.5 residual Cr/Ni/Cu are each ≤.20%; tabulated alloy Cr is not subject to the residual Cr maximum. ; 6.1.7 product-analysis tolerances follow GB/T222 and do not widen the default heat-analysis range; Where Sn is unspecified, limits from a newer edition are not inserted. ; Specific dimensions, product condition and mechanical-property conditions require separate verification; composition alone does not establish suitability for forming a component. ; Alt is total aluminum ≥.020%; when measuring acid-soluble aluminum, Als≥.015% applies; no maximum is specified; The Al field must be interpreted according to the selected measurement basis. ; Table 4 Note a: the lower limit of Si may be agreed to be lower than .10%; the specific agreed range is unknown and shall not be filled in arbitrarily. ; Note b: when hardenability and mechanical properties meet the requirements, the B lower limit may be relaxed to .0005%; Selecting this condition does not represent that performance verification has been completed.

GB/T6478-2001, Table 4, heat analysis wt%; 6.1.4 residual Cr/Ni/Cu are each ≤.20%; alloy Cr ranges are not subject to the residual maximum. ; 6.1.8 product-analysis tolerances require separate verification under GB/T222-1984, Table 2, and do not widen the default heat-analysis range. ; Actual 2001 edition; Composition from editions 2015 or 2025 is not substituted for this edition; specific dimensions and delivery mechanical properties require separate verification. ; Table 4 total aluminum Alt≥.020%; An acid-soluble aluminum determination satisfying Als≥.015% is also acceptable; Default B in this edition is .0005–.0035%. ; 6.1.6 permits contract-specified low carbon .12–.18%, retained separately from the Table 4 default .14–.20%.