20CR2NI4

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 ordinary 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.

Clause 7.1.1 of GB/T3078—2019: quality carbon structural steels comply with GB/T699, and alloy structural steels with GB/T3077; the referenced composition standard must also be displayed. This grade is listed in row 69 of Table 2. Hardness for each delivery condition is listed separately under Table 2; the actual application and delivery condition require separate verification and are not assumed to comply. Cold-drawn steel bars/cold-drawn polished round bars: product-analysis deviations under GB/T222 require separate verification and are not added to heat-analysis ranges. In GB/T3077-2015, Table 1 gives heat analysis and Table 2 gives P/S and residual-element requirements. The final note to Table 1 permits all grades to be ordered as higher or special quality, with the respective suffixes A/E; this record uses the default quality-steel class. Steel for hot pressure working: Cu≤0.20%; the ordinary Cu upper limit does not apply to that use. Explicit alloy ranges in Table 1 take precedence. Where Cr/Ni/Mo is not explicitly specified, the residual limits in Table 2 apply; residual limits are not added to specified alloy-element ranges. Sn/Sb/As must be analysed and recorded on the inspection certificate, with limits agreed where needed; no universal numerical limit is invented here. Product-analysis deviations under GB/T222 are used separately and do not directly widen heat-analysis ranges. Mechanical properties depend on specimen dimensions and the recommended heat-treatment/delivery conditions; this composition review does not establish verification of mechanical properties.

GB/T 3077—1999, Table 1: ladle analysis, mass fraction wt%; this record follows the actual 1999 edition, not the 2015 edition. Grades without suffix A in the table are ordered as quality steel. Table 2 P/S/Cu and residual Mo follow the applicable quality grade; residual Cr/Ni/Mo limits do not override alloy contents specified in Table 1. The chemical composition also applies to ingots, billets and their products; bar scope, mechanical properties and surface-quality requirements do not by themselves guarantee suitability as cold-heading wire. If the processing use is not specified in the contract, machining applies; for hot-pressure processing, Cu≤0.20%, select the applicable condition. Under 6.1.1.2, residual W/V/Ti are analyzed and reported on the certificate; no common limit is stated for unlisted elements, so do not enter zero; Table 1 alloy ranges for W/V/Ti remain applicable. Table 1 Note 2: upgrading to A/E quality or specifying other chemistry by agreement requires a separate order check; do not merge grades or rewrite this row’s C range. Note 4: rare earth 0.05% is a calculated addition; product analysis is for reference, not a guaranteed range. Product-analysis tolerances for steel/billets are separately checked against cited GB/T 222—1984 and do not automatically relax ladle limits.