2024年9月29日，国家市场监督管理总局（国家标准化管理委员会）批准发布511项国家标准，其中GB/T 1231-2024《钢结构用大六角头螺栓连接副》将于2025年4月1日起实施，全面替代2006年发布的系列相关标准（GB/T 1231-2006、GB/T 1230-2006、GB/T 1229-2006、GB/T 1228-2006等）。与2006版相关标准相比，新标准围绕规格扩展、材料性能优化、检测方法创新三大方向进行了系统性调整，具体修订内容包括：
| 项目 | 2006版系列标准 | GB/T 1231-2024 | 变化说明 |
|---|---|---|---|
| 规格范围 | M12~M30 | M12~M36 | 新增M33和M36规格，适应更大尺寸需求。 |
| 材料（10.9S） | 20MnTiB、ML20MnTiB、35VB | 20MnTiB、ML20MnTiB、35VB、42CrMo、ML40CrMo | 新增42CrMo和ML40CrMo材料。 |
| 材料（8.8S） | 35、45、20MnTiB、ML20MnTiB、40Cr、35CrMo、35VB | 35、45、20MnTiB、ML20MnTiB、40Cr、35CrMo、35VB、42CrMo、ML40CrMo | 新增42CrMo和ML40CrMo材料。 |
| 抗拉强度 | 10.9S: 1040 ~ 1240 MPa 8.8S: 830 ~ 1030 MPa | 10.9S: 1040 ~ 1190 MPa 8.8S: 830 ~ 1030 MPa | 10.9S抗拉强度上限从1240 MPa调整为1190 MPa |
| 断面收缩率 | 10.9S: ≥42% 8.8S: ≥45% | 10.9S: ≥48% 8.8S: ≥52% | 断面收缩率要求提高 |
| 冲击吸收功 | 10.9S: ≥47 J 8.8S: ≥63 J | 10.9S: ≥27 J 8.8S: ≥27 J | 冲击吸收功要求降低，且试验温度改为-20°C |
| 芯部硬度 | 10.9S: 312 ~ 367 HV30 (10.9S: 33 ~ 38 HRC) 8.8S: 249 ~ 296 HV30 (8.8S: 24 ~ 31 HRC) | 10.9S: 312 ~ 358 HV30 (10.9S: 33 ~ 38 HRC) 8.8S: 249 ~ 296 HV30 (8.8S: 24 ~ 31 HRC) | 10.9S芯部硬度上限从367 HV30调整为358 HV30 |
| 增碳层 | 无明确要求 | 按GB/T 3098.1规定 | 新增增碳层要求 |
| 35VB材料性能 | 抗拉强度≥785 MPa，断后伸长率≥12%，断面收缩率≥45%，冲击吸收功≥55 J | 抗拉强度≥785 MPa，断后伸长率≥12%，断面收缩率≥45%，冲击吸收功≥50 J | 冲击吸收功从≥55 J 调整为≥50 J。 |
| 35VB冷顶锻试验 | 全尺寸冷顶锻试验，不允许有裂口或裂缝 | 1/2冷顶锻试验（试样压缩至原高度的1/2），不允许有裂口或裂缝 | 简化试验流程，但仍确保材料塑性能力。 |
| 增碳层要求 | 无明确规定 | 按GB/T 3098.1规定，新增增碳层深度及测试方法 | 避免螺栓表面增碳导致的脆性，提升材料性能一致性。 |
| 冲击试验条件 | 缺口类型：U型缺口 试验温度：常温 | 缺口类型：V型缺口 试验温度：-20℃ | 调整低温冲击性能门槛。 |
| 芯部硬度试验 | 按GB/T 230.1或GB/T 4340.1规定，如有争议，以维氏硬度（HV30）试验为仲裁 | 按 GB/T 3098.1 的规定 | 增强测试结果的权威性，减少争议。 |
| 项目 | 2006版系列标准 | GB/T 1231-2024 | 变化说明 |
|---|---|---|---|
| 规格范围 | M12~M30 | M12~M36 | 新增M33和M36规格，适应更大尺寸需求。 |
| 材料（10H） | 35、45、ML35、ML45 | 35、45、ML35、ML45、40Cr | 新增ML45、40Cr材料。 |
| 材料（8H） | 35、45、ML35、ML45 | 35、45、ML35、ML45、40Cr | 新增ML45、40Cr材料。 |
| 硬度规定（10H） | 98HRB ~ 32HRC 222 ~ 304 HV30 | 22HRC ~ 32HRC 239 ~ 304 HV30 | 10H硬度下限从222 HV30调整为239 HV30 |
| 螺纹加工要求 | 无热处理后攻丝的明确规定 | 允许热处理后攻丝（需供需双方协议） | 提高加工灵活性，优化高强度螺母的螺纹精度。 |
| 项目 | 2006版系列标准 | GB/T 1231-2024 | 变化说明 |
|---|---|---|---|
| 规格范围 | 12mm~30mm | 12mm~36mm | 新增33mm和36mm规格，适应更大尺寸需求。 |
| 材料 | 35、45 | 35、45 | 无变化。 |
| 型式 | 单一型式（内倒角） | 新增“垫圈A”（内、外倒角）和“垫圈B”（仅外倒角） | 区分螺栓头下和螺母下垫圈的倒角形式，优化装配接触面。 |
| 项目 | 2006版系列标准 | GB/T 1231-2024 | 变化说明 |
|---|---|---|---|
| 扭矩系数统计指标 | 标准偏差≤0.010 | 变异系数 | 通过变异系数（标准差/均值）衡量离散度，更科学反映批次稳定性。 |
| 扭矩系数相关公式 | 扭矩系数公式 | 扭矩系数 变异系数公式 | 新增变异系数相关计算公式 。 |
| 扭矩系数试验螺栓预拉力 | （表8）拉力范围是拉力平均值的0.2倍左右 | （表14）拉力范围是拉力平均值的0.1倍左右 | 缩减预拉力范围，提升试验结果的稳定性和连接可靠性 |
| 扭矩系数试验转速要求 | 无具体转速要求 | 拧紧螺母转速宜小于5r/min，且速度均匀 | 控制安装速度，减少摩擦热对扭矩系数的影响。 |
| 脱碳/增碳试验检验规则 | 无针对脱碳/增碳的专项检验规则 | 新增：“按批抽取，样本 | 确保脱碳、增碳层符合要求，提升表面质量控制。 |
| 标签内容 | 无标签要求 | 需包含：本文件编号、规格、表面处理类型、制造者信息、批号、装箱数量等 | 强化产品追溯信息，满足质量追溯需求。 |
GB/T 1231-2024通过扩大规格范围、优化材料性能指标、完善检测技术方法及强化全流程质量控制等系统性升级，显著提升了高强螺栓连接副的适配能力和工程可靠性，为现代工程项目提供更加科学规范且灵活多样的技术支撑。具体实施细则和完整技术条款，请以《GB/T 1231-2024》及《GB/T 1231-2006》等标准文件内容为准。相关产品信息：
GB /T 1231 (bolt) - 2024-钢结构用高强度大六角头螺栓- 易紧通
GB /T 1231 (washer) - 2024-钢结构用高强度垫圈- 易紧通
GB /T 1231 (nut) - 2024-钢结构用高强度大六角螺母- 易紧通
GB /T 1231 (assemblies) - 2024-钢结构用高强度大六角头螺栓连接副- 易紧通
GB /T 1231 (Specifications) - 2024-钢结构用高强度大六角头螺栓、 大六角螺母、垫圈技术条件- 易紧通
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