20CRMOA

GB/T 3077-2015 Table 1 gives ladle analysis; Table 2 gives P/S and residual-element requirements. The final note to Table 1 allows ordering any grade as higher or special quality by adding A or E after the grade; this record is higher-quality steel. For steel used in hot-pressure working, Cu ≤0.20%; the ordinary Cu maximum does not apply to this use. Explicit alloy ranges in Table 1 take priority; for Cr/Ni/Mo not specified there, use the residual limits in Table 2 and do not add residual limits on top of alloying-element ranges. Sn/Sb/As must be analyzed and recorded on the inspection certificate; any needed limits require agreement, and no generic numerical limits are invented here. Product-analysis deviations are handled separately under GB/T 222 and do not directly expand ladle limits. Mechanical properties depend on specimen dimensions and the recommended heat-treatment/delivery condition; this composition review does not constitute verification of properties.

Q/BQB 517—2023, official original on the Baosteel website, Table 1, row 84; cast-analysis mass fraction wt%. Table footnote a: residual Cr≤0.20, Ni≤0.20, Cu≤0.20, Mo≤0.06 wt%; where this row specifies otherwise, its requirement for that element takes precedence. Unlisted elements and special agreement requirements must not be treated as zero or assumed guarantees; permitted product-analysis deviations are governed separately by GB/T 222. Wire rod is delivered hot rolled; stricter P/S under Z1 and special surface or inclusion quality must be confirmed under normative Annex A and the contractual ordering codes. Fixed mechanical properties must not be inferred from the chemistry table.