GB/T 14977-2025 English PDFGB/T 14977: Historical versions
Basic dataStandard ID: GB/T 14977-2025 (GB/T14977-2025)Description (Translated English): General requirement for surface condition of hot-rolled steel sheet and plate Sector / Industry: National Standard (Recommended) Date of Implementation: 2026-03-01 Older Standard (superseded by this standard): GB/T 14977-2008 GB/T 14977-2008: General requirement for surface condition of hot-rolled steel plates---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.General requirement for surface condition of hot-rolled steel plates ICS 77.140.50 H46 National Standards of People's Republic of China Replace GB/T 14977-1994 General requirements for surface quality of hot rolled steel sheets Released on.2008-12-06 2009-10-01 implementation General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China China National Standardization Administration issued ForewordThis standard is modified to use EN10163-2.2004 "Hot-rolled steel sheet, wide flat steel and section steel surface condition delivery requirements Part 2. Steel Plate and wide flat steel. The main technical differences between this standard and EN10163-2.2004 are. --- Added provisions for 5.3.1.2.1 and 5.3.1.2.3 to the defect; --- Added specific provisions for stacking height when welding; --- Added the chapter "6 Value Repair". This standard replaces GB/T 14977-1994 "General Requirements for Surface Quality of Hot Rolled Steel Sheets". Compared with the original standard, the main changes are as follows. --- Expand the scope of application of the standard to a steel plate of 3mm ~ 400mm; --- Added "2 normative references" chapter; --- Added the "4 classification" chapter, the surface quality is divided into 2 categories, each category is divided into 3 levels; --- Increase the general requirements of the surface of the steel plate; --- The modification of the area of the surface discontinuity has been modified; --- Removed 4.2.1 from the original standard; --- Class A defects increased by 5.3.2.2.1; --- Detailed provisions for the repair of defects; --- Made specific requirements for welding repair. Appendix A and Appendix B of this standard are informative annexes. This standard was proposed by the China Iron and Steel Association. This standard is under the jurisdiction of the National Steel Standardization Technical Committee. This standard is mainly drafted by. Shougang Corporation, Tianjin Iron and Steel Co., Ltd., Metallurgical Industry Information Standards Institute, Angang Steel Co., Ltd. the company. The main drafters of this standard. Shi Li, Zhang Bingcheng, Xu Keliang, Wang Xiaohu, Pu Zhimin, Wang Liping, Sun Guoqing. This standard was first published in.1994. General requirements for surface quality of hot rolled steel sheets1 ScopeThis standard specifies the terms and definitions, classification, requirements, and numerical revision of the surface quality of hot rolled steel sheets. This standard is applicable to single-rolled hot-rolled steel sheets with a thickness of 3mm to 400mm and sheared steel sheets cut from hot rolled coils. The following are referred to as steel plates.2 Normative referencesThe terms in the following documents become the terms of this standard by reference to this standard. All dated references, followed by all Modifications (not including errata content) or revisions do not apply to this standard, however, parties to agreements based on this standard are encouraged to study Is it possible to use the latest version of these files? For undated references, the latest edition applies to this standard. YB/T 081 Metallic technical standards for numerical repair and determination of test values3 Terms and definitionsThe following terms and definitions apply to this standard. 3.1 In addition to cracks, crusting and cracking, surfaces with depth and/or area not greater than the specified limit are discontinuous. 3.2 Includes all cracks, crusting and cracking, surface discontinuities where the depth and/or area is greater than the specified limit. Note. A description of common surface discontinuities is given in Appendix A (informative).4 classification4.1 Surface quality is divided into two categories. A and B. --- Class A. The surface quality should meet the requirements of 5.3.1 and 5.4.1.3. The residual thickness of the surface discontinuity and the grinding part can be less than The minimum thickness allowed for the steel plate. --- Class B. The surface quality shall comply with the requirements of 5.3.2 and 5.4.1.4, and the remaining thickness of the surface discontinuity and the grinding part shall not be less than The minimum thickness allowed for the steel plate. 4.2 Each category is further divided into 1, 2, and 3. -- Level 1. Allows for weld repair after shoveling and/or grinding, and meets the requirements of 5.4.2.2.1. -- Level 2. Soldering is allowed only if both parties agree and are indicated in the contract and meet the requirements of 5.4.2.2.2. -- Level 3. Welding repair is not allowed. Note. Table B. 1 gives the classification of surface quality and its requirements.5 requirements5.1 General requirements for steel sheet surfaces 5.1.1 Regardless of whether the steel plate is descaled or not, the manufacturer shall take necessary measures to ensure that the surface quality of the steel plate meets the requirements. Production plant Only consider the surface discontinuities visible to the naked eye. Iron oxide scales produced by rolling and heat treatment may hide surface discontinuities. 5.1.2 If the user requires all visible surface discontinuities to be identified, evaluated, trimmed (if necessary) prior to delivery, the descaling product should be Order. 5.1.3 If the user finds that the material is defective in the subsequent descaling or processing, and the defect is caused by the manufacturer, the manufacturer is allowed to press The requirements of the product standard are revised and resubmitted. 5.1.4 If the surface quality category and grade are not included in the contract or in the product standard but are not specified, they shall be regarded as Class A1. 5.2 Determination of surface discontinuity depth and area of influence 5.2.1 Determination of depth In order to distinguish between surface discontinuities and defects, a representative surface discontinuity depth is determined as necessary. Measurement should be from the product list Face to face. The depth was determined after grinding to remove representative surface discontinuities. 5.2.2 Determination of the area affected If necessary, measure the area of influence of surface discontinuity as follows. 5.2.2.1 The isolated surface is discontinuous, drawing a continuous line 20 mm away from the discontinuous perimeter of the surface, or 20 mm from its edge Draw a rectangle to determine the area of influence, as shown in Figure 1. 5.2.2.2 Uneven surface of the aggregated surface. draw a continuous line 20mm along the discontinuous perimeter of the set of surfaces, or draw a rectangle, The longitudinal side and the horizontal margin are discontinuously connected to the surface of the group of 20 mm; if the surface of the group is less than 20 mm from the edge of the steel sheet, the edge of the steel sheet is The edge is correct. As shown in Figure 2. 5.2.2.3 Strip-shaped surface discontinuity. draw a rectangle whose longitudinal and lateral margins are discontinuously connected to the surface of the set of 20 mm, if the surface of the group If the edge of the discontinuous steel plate is less than 20mm, the edge of the steel plate shall prevail, as shown in Figure 3. 5.2.2.4 Multiple surface discontinuous edge spacings may be considered as a converging surface discontinuity within 40 mm (including aggregated surfaces not Continuous and strip surfaces are discontinuous). The unit is mm 1---horizontal line. Figure 1 Determination of isolated surface discontinuity affecting area The unit is mm 1---horizontal line. Figure 2 Determination of the area of the discontinuous surface of the aggregated surface The unit is mm Figure 3 Determination of the area of discontinuity affecting single or multiple strip surfaces 5.3 Dressing requirements 5.3.1 Class A 5.3.1.1 Defects 5.3.1.1.1 In addition to cracks, crusting and cracking, when the surface discontinuity does not exceed the requirements of Table 1, and the minimum thickness of the steel plate is ensured, It is considered to be inevitable in the production process, and it is allowed to exist regardless of the quantity. 5.3.1.1.2 Except for cracks, crusting and cracking, when the surface discontinuity does not exceed the specified in Table 1, the remaining thickness is less than the minimum of the steel plate. Thickness, and the affected area does not exceed 15% of the inspection area, and may not be trimmed. Table 1 is in millimeters 5.3.1.1.3 Except for cracks, crusting and cracking, when the surface discontinuity exceeds Table 1, does not exceed the requirements of Table 2, and the remaining thickness is not If the minimum thickness of the steel sheet is less than 5% of the inspection area, the total thickness of the steel sheet may not be trimmed. 5.3.1.1.4 Except for cracks, crusting and cracking, when the surface discontinuity exceeds Table 1, does not exceed the requirements of Table 2, but the remaining thickness of the steel plate If the degree is less than the minimum thickness of the steel plate, the affected area may not exceed 2% of the inspection area, and the trimming may not be performed. Table 2 is in millimeters 5.3.1.2 Defects 5.3.1.2.1 The depth shall not exceed the requirements of Table 1, but the remaining thickness is less than the minimum thickness of the steel plate, and the affected area exceeds 15% of the inspection area. The surface is not continuous and should be trimmed. 5.3.1.2.2 If the depth exceeds Table 1, but does not exceed the requirements of Table 2, the surface discontinuity that affects the area greater than 5% of the inspection area shall be performed. trim. 5.3.1.2.3 The depth exceeds Table 1 but does not exceed the requirements of Table 2, and the remaining thickness is less than the minimum thickness of the steel plate, and the affected area exceeds the inspection surface. A 2% surface discontinuity should be trimmed. 5.3.1.2.4 Surface discontinuities exceeding the limits specified in Table 2 shall be trimmed regardless of the number. 5.3.1.2.5 Cracks, crusting and cracking usually have a certain depth and sharpness, which will affect the use of the product, regardless of its depth and number. The amount should be trimmed. 5.3.2 Class B As long as the surface discontinuity and the remaining thickness of the trimmed area are not less than the minimum thickness of the steel sheet, 5.3.1.1 and 5.3.1.2 apply. 5.4 dressing process 5.4.1 Grinding 5.4.1.1 The grinding should be ground and the smoothing surface should be smoothly transitioned to the surface of the steel plate. Magnetic particle testing or penetration method To prove that the defect has been completely removed. 5.4.1.2 Allow the manufacturer to grind the entire surface of the steel plate. However, the remaining thickness after grinding must ensure the minimum thickness of the steel plate. 5.4.1.3 Class A 5.4.1.3.1 Class A defects allow their grinding depth to exceed the minimum thickness of the steel plate. 5.4.1.3.2 When the dressing depth meets the requirements of Table 3, the grinding area smaller than the minimum thickness of the steel plate shall not exceed 15% of the inspection area. 5.4.1.3.3 When the dressing depth is greater than Table 3 and meets the requirements of Table 4, the sum of the single-face grinding areas less than the minimum thickness of the steel plate shall not exceed 2% of the inspection area. If the surface area of the steel plate is greater than 12.5 m2, the single grinding area smaller than the minimum thickness of the steel plate shall not be large. At 0.25m2. 5.4.1.3.4 The requirements of Table 4 may also apply to the sum of the dressing depths of the two dressing surfaces at the relative position of the steel sheet surface. Table 3 is in millimeters Table 4 is in millimeters 5.4.1.4 Class B The remaining thickness of the steel plate after grinding shall not be less than the minimum thickness of the steel plate. 5.4.2 Welding repair 5.4.2.1 General requirements 5.4.2.1.1 The harmful defects on the steel plate shall be completely removed before the welding repair, and the depth of the removed part shall be within 30% of the nominal thickness of the steel plate. 5.4.2.1.2 Before the edge of the steel plate is welded, the groove depth measured from the inner edge is at most 30 mm less than the nominal thickness. 5.4.2.1.3 There shall be no defects on the edge of the welded part of the steel plate that are not fused, undercut, cracked or otherwise affected. Stack height should be high The rolling surface is more than 1.5mm, and then the stacking height is removed by shovel or grinding equal method; after treatment, the thickness of the sanding area should ensure the most Small thickness. 5.4.2.1.4 Heat treatment The steel plates delivered after welding shall be heat treated accordingly. 5.4.2.1.5 After welding, it shall be tested by ultrasonic, X-ray, magnetic particle inspection or penetrant inspection. When the demander does not specify a method, by production The factory decides by itself. 5.4.2.1.6 If specified in the contract, for all weld repairs, the manufacturer shall provide a report with a sketch indicating the size of the defect and All details of the part and the repair process, including welding consumables, non-destructive testing and post-weld heat treatment. 5.4.2.2 Classification of weld repair and its limits 5.4.2.2.1 Level 1. The area of individual weld repair shall not exceed 0.125m2; the total weld repair area shall not exceed 0.125m2 or shall not exceed the inspection surface. 2% (take the larger of the two). If the distance between the dressing and the repaired area is less than the average width of the treated area, it shall be regarded as one region. 5.4.2.2.2 Level 2. Welding repair is permitted only if agreed upon at the time of ordering and noted in the contract. In this case, it can be specified Different requirements than 5.4.2.2.1. 5.4.2.2.3 Level 3. Welding repair is not allowed.6 numerical repairThe numerical rounding shall comply with the provisions of YB/T 081.Appendix A(informative appendix) Common surface discontinuity description It appears on the rolled surface in a variety of shapes, thicknesses and frequencies. Press-in of the scale is usually caused by insufficient removal of the scale during hot rolling, hot rolling or treatment. These defects may be distributed over a fixed distance or irregularly over the entire length and width of the rolled product. Indentations (depressions) and hot-rolled marks (bumps) are generally considered to be caused by natural wear of the rolls or transfer rolls. Mechanical abrasion of the surface, mostly parallel or perpendicular to the rolling direction. They are likely to have a slight roll and rarely contain iron oxide skin. This damage is caused by friction during the relative movement between the rolling stock and the equipment. Irregular and scaly small surface defects. The delamination extends in the rolling direction, the extent of which depends on the amount of deformation. In some They are still connected to the base metal and appear as fine crusting particles. The bubbles are located below the skin and are different in shape and size and are visible during hot rolling. Fine non-metallic internal inclusions that extend in the rolling direction and have a distinct color. Thin lines with broken surfaces. A partially overlapping material that is joined to the matrix material. There are more non-metallic inclusions and/or iron oxide scales in the heavy skin. The cracking is mainly caused by the elongation or elongation of the defects in the semi-finished product during the rolling process. Book GB/T 14977-2008Appendix B(informative appendix) Classification of surface quality and its requirements Table B. 1 gives the classification of surface quality and its requirements. Table B. 1 Classification of surface quality and its requirements After the category cutting/repairing and repairing, the welding repair is not allowed to be welded by the agreement. Class A (The remaining thickness of the dressing area meets the requirements of 5.4.1.3) Level 1 × Level 2 × Level 3 × Class B (The remaining thickness of the dressing area meets the requirements of 5.4.1.4) Level 1 × Level 2 × Level 3 × 8002- T/B ...... |
