CO2焊/喷射高碳铬铁合金粉复合堆焊层耐磨性

Abrasion performance of metal deposited with CO2 arc welding spraying high-carbon chromium iron powder

关键词:  二氧化碳气体保护焊  喷射送粉  高碳铬铁  耐磨性

Key words:  CO₂ gas shielded welding  spraying powder  high-carbon chromium iron  abrasion performance

摘要:

采用CO₂焊/喷射送粉复合堆焊新方法,通过喷射高碳铬铁粉体,研究送粉量及送粉气流量对堆焊层硬度及耐磨性的影响,并通过XRD,TEM等分析方法研究了堆焊层组织结构与耐磨性的影响规律.结果表明,当送粉速度800 g/h,送粉气体流量5L/min时,堆焊层硬度为55 HRC,耐磨性与单纯H08Mn2Si焊丝堆焊相比提高了4倍;喷入高碳铬铁后,加速了熔池的冷却速度,增加了不平衡组织的产生,促使堆焊层产生大量的位错緾结、板条马氏体的断裂和扭曲变形、孪晶马氏体不规则排列;喷入的高碳铬铁可作为生核质点,使焊缝晶粒尺寸细小,产生碳化铬等硬质相,提高了堆焊层的耐磨性.

Abstract:

A new developed CO₂ arc welding-spray powder muti surface method was used to study the effect of powder feed rate and airflow rate on the hardness and abrasion performance of the deposited metal by spraying high-carbon chromium iron powder. The microstructure and phase of the deposited metal were studied by XRD and TEM method. The results show that the hardness can reach 55 HRC when the powder feed rate is 800 g/h and the airflow rate is 5 L/min. The abrasion performance of the deposited metal by spraying high-carbon chromium iron powder is four times than that by only using the H08Mn2Si welding wire. Spraying high-carbon chromium iron powder will increase the cooling rate of molten pool and accelerate the production of the non-equilibrium microstructure including large amount of dislocation entanglements, the crack and distortion of the lath martensite and the irregular configuration twin-martensite. The sprayed high-carbon chromium iron powder could act as the nucleation particles to make the weld grain size finer. The abrasion performance of the deposited metal was improved for the creation of the chrome carbide.