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目前,铸铁件冷焊多采用昂贵的镍基焊条.采用价格便宜的铸铁焊条冷焊,其焊缝强度低.塑性差、易出现裂纹、白口组织,特别是接头硬度高,加工性能差.为此,研制了一种新型同质铸铁冷焊焊条.这种焊条采用H08A焊芯,在冷焊状态下达到下述设计要求:①有效地解决裂纹、白口问题;②接头硬度低,机械加工性能好,焊缝强度高;③具有良好的工艺性能.铸铁冷焊焊条药皮中加入多种石墨化剂.复合变质剂及稀土、硅钙合金.为减少石墨化元素烧损,采用了弱氧化性的萤石-长石渣系.1 实验内容及结果分析实验采用φ4.0 mm焊条,交流施焊,焊前试板不预热,焊后的自然冷却,焊条焊前280℃×1h烘焙.试板为灰口铸铁.焊接电流160～170A,电弧电压25～30V,焊接速度150mm/min.焊缝的化学成分见下表.焊缝抗拉强度315MPa.硬度试验结果:
At present, the cast iron parts cold welding using expensive nickel-based electrode.Using cheap cold welding of cast iron electrode, the weld strength is low.Plastic poor, prone to cracking, white mouth organization, especially the joint hardness, poor processing performance. For this reason, a new type of homogenized cast iron cold welding electrode has been developed, which uses H08A welding core to achieve the following design requirements under cold welding conditions: ① effectively solve the problem of cracks and white mouth; ② low joint hardness, Good processing performance, high weld strength; ③ has good process performance cast iron cold welding electrode coating added a variety of graphitization agent compound modifier and rare earth, calcium-calcium alloy.In order to reduce the burning of graphitized elements, using Weak oxidizing feldspar - feldspar slag system.1 Experimental contents and results analysis The experiment using φ4.0 mm electrode, AC welding, pre-welding test plate is not preheated, natural cooling after welding, the electrode before welding 280 ℃ × 1h baking. The test plate is gray cast iron. Welding current 160 ~ 170A, arc voltage 25 ~ 30V, welding speed 150mm / min. The chemical composition of the weld is shown in the following table. Weld tensile strength 315MPa. Hardness test results: