1 Products Description
Red copper is an important metal material in industry ‚ Excellent thermal conductivity, normal temperature and low temperature plasticity ‚ It has good corrosion resistance to atmosphere, seawater, non-oxidizing acid and calcium salt. But its strength is low ‚ Significant ‚ If it is used as the structural material of the container alone ‚ Its application in large-scale chemical equipment is limited. If work hardening is used to improve strength ‚ Its plasticity will be greatly reduced ‚ At the same time, its corrosion resistance is damaged ‚ Therefore, its excellent corrosion resistance to some media Point is difficult to fully play. Emergence of explosive bonding method for dissimilar metals ‚ So that copper can be used in large quantities in chemical equipment ‚ However, when the weldability temperature of copper exceeds 300 ℃ ‚ The oxidation ability of copper is significantly enhanced ‚ Oxidation to form Cu2O ‚ Forming low melting point eutectic with Cu; At high temperature ‚ Cu can be mixed with impurity elements (such as Pb) in the base metal or welding wire ‚ Bi ‚ S, etc.) form eutectic with low melting point ‚ During welding cooling ‚ Low-melting eutectic aggregates a lot of grain boundaries ‚ Weakening the intergranular strength; Copper has good thermal conductivity ‚ Large linear expansion coefficient ‚ Welding cooling. Fast cooling speed of weld in the process ‚ Welding stress is large.
2 Weldability analysis of copper/steel composite plate
Copper and copper alloy clad steel plate is made of copper/steel explosive composite ‚ Copper as the cladding ‚ Steel as base ‚ Its chemical composition and mechanical properties.
3Hot crack problem
The Copper and copper alloy clad steel plate has the following characteristics: the clad copper is single-phase α organization ‚ During welding heating ‚ Copper is easily heated and grows to form coarse single-phase α Organization; When the temperature exceeds 300 ℃ ‚ The oxidation ability of copper is significantly enhanced ‚ Oxidation to form Cu2O ‚ Forming low melting point eutectic with Cu; At high temperature ‚ Cu can be mixed with impurity elements (such as Pb) in the base metal or welding wire ‚ Bi ‚ S, etc.) form eutectic with low melting point ‚ During welding cooling ‚ Low-melting eutectic aggregates a lot of grain boundaries ‚ Weakening the intergranular strength; Copper has good thermal conductivity ‚ Large linear expansion coefficient ‚ Fast cooling rate of weld during welding cooling ‚ Welding stress is large. Therefore, due to the existence of eutectic with low melting point in high temperature zone during welding ‚ Hot cracks are easily formed under welding stress.
4 Welding process - process plan and groove form
The intermediate transition layer is used to weld the copper/steel composite plate. Manual electrode arc welding for base welding ‚ Manual TIG welding is used to weld copper/steel transition layer and copper clad layer. The test shall be carried out in two ways: welding the base layer before welding the cladding layer and welding the cladding layer before welding the base layer.
5 Selection of welding materials
Welding of Copper and copper alloy clad steel plate ‚ The joint strength shall be guaranteed ‚ Corrosion resistance of composite layer ‚ Prevent the formation of copper-steel alloy weld and mechanical mixture at the interface of the transition layer when welding copper/steel ‚ At the same time, prevent the generation of welding cracks and pores in the copper clad layer. therefore ‚ When welding copper/steel composite plate ‚ The following requirements shall be met: ① When welding clad copper ‚ The selected welding material shall be able to effectively control the impurity content in the weld and improve the deoxidization ability of the weld ‚ Avoid the occurrence of hot cracks and pores in the weld ‚ Make the joint have good corrosion resistance; ② The composition of the welding wire in the transition layer shall be able to reduce the impurities and content of the weld ‚ Good deoxidization and impurity removal ‚ And it shall have good solid solubility with the base layer and the composite layer; ③ The welding material of base steel shall be selected according to the principle of equal strength ‚ To ensure that the joint strength meets the design requirements. The selection of welding materials for each part is shown in Table 2.
Cim npe nrov: copper and copper alloy clad steel plate, China, manufacturers, suppliers, factory, customized, buy, price, quality, quotation, pricelist, in stock
