Technical Research On Pinch Roller Of Surfacing Welding

Pinch roll is an important transmission part of roll steel equipment. Many countries use surfacing welding to make pinch roll. surfacing welding for pinch rolls is similar with surfacing welding for hot rolls. Since the surfacing welding filler materials contain high carbon equivalent with high hardness and low plasticity, it is very easy to produce cold cracks and hot cracks in welding, especially hot cracks, it can affect the quality of pinch roller surfacing welding. Therefore, this paper mainly concern on the study and how to eliminate cracks.This paper studies the cracking resistances of pinch roll, and analysis the preheating surfacing welding of pinch rolls in different temperatures. It also analyses the causes of cold crack and hot crack. Besides, it studies the influences of preheating and intermediate layers on cold crack and hot crack, and proofs it experimentally . Control specific factor during production, in order to eliminate cracks of welding layer and improve the quality of products.Through cracking resistance experiments of Soudokay258—SA welding wire /RECORD SA flux and CrWNiMnSi welding wire/SJ6-1 flux , this paper proves that the latter is better than the former .Also, by using superior low S,P of H09Mn welding wire and SJ204 flux to carry out intermediate layers can prevent hot cracks;Through analysis and experiments of the influence which dilution ratio on chemical components and cracking resistance, it proves that overlapping coefficient is a key factor of surfacing welding layers dilution ratio. The results show that the key factors of affect hot crack are dilution ratio, impurity elements and stress condition. Meanwhile, it also tell us that when the weld bead overlapping rate is 50% , the dilution rate is low ,and the weld formation is better.According to the research results of theory and experiment, it sets up two different types of surfacing welding, and puts into practice on the basis of technology. Through examination of defect and hardness, it shows that the correctness of technology. It has directed meaning and useful value to production.