1756-ENBT模块备件

1756-ENBT A

3.消除压力：
6.3.1钢铁预处理，以降低腐蚀风险
由钢制成的氢脆零件，具有：
极限抗拉强度大于1000 Mpa（硬度：
31 HRC或更大），其已被机加工、磨削或冷加工
应在热处理后进行成型或冷矫直
当工程师指定时，要求进行应力消除热处理
买方提供的抗拉强度，
关于广泛使用的预处理列表，可参考规范B 849。
6.3.2喷丸：可能需要在电镀前对表面进行喷丸处理
高强度钢零件会产生残余压缩应力
表面应力，可减少疲劳损失
强度和提高电镀后的抗应力腐蚀性。
（见补充要求）。
6.3.3设计用于在以下条件下无限使用寿命的钢部件：
动态载荷应进行喷丸或旋转襟翼喷丸处理。
注6：控制喷丸是选方法，因为：
是旋转襟翼喷丸无效的几何形状。见S11.2。
6.3.3.1除非另有规定，否则应进行喷丸处理
在需要涂层的所有表面上完成
以及当它们包含切口时的所有直接相邻表面，
或截面尺寸的其他突然变化
将被浓缩。
6.4货架部件的位置应尽可能减少
在空腔和孔洞中捕获氢气，允许自由流动
溶液在所有表面上循环，以获得均匀的
涂层厚度。机架或导线标记在机架中的位置
涂层应在生产商和供应商之间达成一致
买方
6.5电镀工艺：
6.5.1为了获得一致的涂层性能，镀液必须：
定期监测pH值、温度、镍和
次磷酸盐。应补充电镀溶液
应尽可能频繁地保持溶液的浓度
镍和次磷酸盐在设定值的90%和100%之间。
使用统计方法确定控制限
并且可以采用分析频率来确保质量
产生沉积物。
6.5.2零件的机械移动和搅拌
建议使用镀液来提高涂层的平滑度和硬度
均匀性，并防止因氢引起的点蚀或条纹
泡沫。
6.6还原用钢铁的后涂层处理
由以下材料制成的零件存在氢脆风险：
极限抗拉强度为1000 Mpa（硬度为
31 HRC或更大）以及表面硬化零件应：
要求后涂层消除氢脆烘烤
当买方规定时，抗拉强度应为：
由买方提供。关于广泛使用的后处理列表，可参考规范B 850。
6.6.1热处理好在1小时内进行
h，但不超过3 h
减少氢脆风险的钢制零件。总共
在这种情况下，热处理的持续时间应从
各部分整体达到规定值的时间
温度
6.6.2具有实际抗拉强度的高强度钢零件
大于1000MPa（对应的硬度值为300
HV10、303 HB或31 HRC）和表面硬化零件应：
根据规范B 850进行涂层后处理。
6.7电镀后的热处理，以提高对涂层的附着力
提高涂层对各种基材的附着力
应尽快进行表3中的热处理
电镀后实用（见4.3）。
6.8电镀后的热处理以增加硬度：
6.8.1为了提高涂层的硬度，需要进行260°C以上的热处理。表3描述了热量
大硬度处理。
6.8.2见附录3和附录4以及指南B 656；无花果。X1.2
以及图。X1.3。
6.8.3应在260°C下进行超过20小时的热处理
用于减少表面硬度和强度的损失
一些铁基金属。避免快速加热和冷却
电镀零件。必须留出足够的时间，以便安装大型零件
达到烤箱温度。
注7——达到大硬度的时间长度随时间变化
沉积物中的磷含量。可能存在高磷矿床
需要更长的时间或更高的温度或两者。单个合金
应测试可达到的大硬度，尤其是在较低温度和较长时间的条件下。
注8-惰性或还原性气氛或真空足以防止
对于260°C以上的热处理，建议采用氧化处理。不要使用煤气
含氢的高强度钢部件。
7.要求
7.1工艺涂层应通过化学还原反应从水溶液中制备。
7.2验收要求：这些要求包括：
放置在每个批次或批次上，并可通过测试
电镀零件。
7.2.1外观：
7.2.1.1涂层表面应具有均匀的金属光泽
外观无明显缺陷，如泡罩、凹坑等，
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1756-ENBT A

1756-ENBT A

3 Stress Relief: 6.3.1 Pretreatment of Iron and Steel for Reducing the Risk of Hydrogen Embrittlement—Parts that are made of steel with ultimate tensile strength of greater than 1000 Mpa (hardness of 31 HRC or greater), that have been machined, ground, cold formed, or cold straightened subsequent to heat treatment, shall require stress relief heat treatment when specified by the purchaser, the tensile strength to be supplied by the purchaser, Specification B 849 may be consulted for a list of pretreatments that are widely used. 6.3.2 Peening—Peening prior to plating may be required on high-strength steel parts to induce residual compressive stresses in the surface, which can reduce loss of fatigue strength and improve stress corrosion resistance after plating. (See Supplementary Requirements). 6.3.3 Steel parts which are designed for unlimited life under dynamic loads shall be shot peened or rotary flap peened. NOTE 6—Controlled shot peening is the preferred method because there are geometry’s where rotary flap peening is not effective. See S11.2. 6.3.3.1 Unless otherwise specified, the shot peening shall be accomplished on all surfaces for which the coating is required and all immediate adjacent surfaces when they contain notches, fillets, or other abrupt changes of section size where stresses will be concentrated. 6.4 Racking—Parts should be positioned so as to minimize trapping of hydrogen gas in cavities and holes, allowing free circulation of solution over all surfaces to obtain uniform coating thickness. The location of rack or wire marks in the coating shall be agreed upon between the producer and purchaser. 6.5 Plating Process: 6.5.1 To obtain consistent coating properties, the bath must be monitored periodically for pH, temperature, nickel and hypophosphite. Replenishments to the plating solution should be as frequent as required to maintain the concentration of the nickel and hypophosphite between 90 and 100 % of set point. The use of a statistical regimen to establish the control limits and frequency of analysis may be employed to ensure quality deposits are produced. 6.5.2 Mechanical movement of parts and agitation of the bath is recommended to increase coating smoothness and uniformity and prevent pitting or streaking due to hydrogen bubbles. 6.6 Post Coating Treatment for Iron and Steel for Reducing the Risk of Hydrogen Embrittlement—Parts that are made of steel with ultimate tensile strengths of 1000 Mpa (hardness of 31 HRC or greater), as well as surface hardened parts, shall require post coating hydrogen embrittlement relief baking when specified by the purchaser, the tensile strength to be supplied by the purchaser. Specification B 850 may be consulted for a list of post treatments that are widely used. 6.6.1 Heat treatment shall be performed preferably within 1 h but not more than 3 h of plating on plated after plating of steel parts to reduce the risk of hydrogen embrittlement. In all cases, the duration of the heat treatment shall commence from the time at which the whole of each part attains the specified temperature. 6.6.2 High-strength steel parts with actual tensile strengths greater than 1000 MPa (corresponding hardness values 300 HV10, 303 HB or 31 HRC) and surface hardened parts shall be processed after coating in accordance with Specification B 850. 6.7 Heat Treatment After Plating to Improve Adhesion—To improve the adhesion of the coating to various substrates, the heat treatments in Table 3 should be performed as soon as practical after plating (see 4.3). 6.8 Heat Treatment After Plating to Increase Hardness: 6.8.1 To increase the hardness of the coating a heat treatment of over 260°C is required. Table 3 describes the heat treatment for maximum hardness. 6.8.2 See Appendixes 3 and 4 and Guide B 656; Figs. X1.2 and Figs. X1.3. 6.8.3 A heat treatment at 260°C for greater than 20 h should be used to reduce the loss of surface hardness and strength of some ferrous basis metals. Avoid rapid heating and cooling of plated parts. Sufficient time must be allowed for large parts to reach oven temperature. NOTE 7—The length of time to reach maximum hardness varies with the phosphorus content of the deposit. High phosphorus deposits may require longer time or a higher temperature, or both. Individual alloys should be tested for maximum hardness attainable, especially for conditions of lower temperatures and longer times. NOTE 8—Inert or reducing atmosphere or vacuum sufficient to prevent oxidation is recommended for heat treatment above 260°C. Do not use gas containing hydrogen with high-strength steel parts. 7. Requirements 7.1 Process—The coating shall be produced from an aqueous solution through chemical reduction reaction. 7.2 Acceptance Requirements—These requirements are placed on each lot or batch and can be evaluated by testing the plated part. 7.2.1 Appearance: 7.2.1.1 The coating surface shall have a uniform, metallic appearance without visible defects such as blisters, pits, pimples, and cracks (see 9.2). 7.2.1.2 Imperfections that arise from surface conditions of the substrate which the producer is unable to remove using conventional pretreatment techniques and that persist in the coating shall not be cause for rejection (see 6.1). Also, discoloration due to heat treatment shall not be cause for rejection unless special heat treatment atmosphere is specified (see section 5.1.9). 7.2.2 Thickness—The thickness of the coating shall exceed the minimum requirements in Table 2 as specified by the service condition agreed to prior to plating (see 9.3). After coating and if specified, the part shall not exceed maximum dimension on significant surface (see section 5.1.3