Medium carbon steel welding technology is introduced
Views: 0 Author: Site Editor Publish Time: 2016-09-28 Origin: Site
Preheating is helpful to reduce the highest hardness of medium carbon steel heat affected area, prevent to produce cold crack, this is the main technological measures, the welding of medium carbon steel preheating can also improve the joint plasticity, reduce the residual stress after welding.Usually, 35 and 45 steel preheating temperature is 150 ~ 250 ℃ carbon thickness and stiffness is very big, no matter how high or cracks tend to be large, can preheat temperature up to 250 ~ 250 ℃.
If welding is too big, overall preheating have difficulty, can undertake local preheating, local heating heating in the range of joint on each side of 150 ~ 200 mm.
Second, the electrode
When conditions permit preferable alkaline welding rod.
Three, groove form
Will try to open the weldment U type groove welding should be carried out.If it is a casting defects, digging out the groove shape should be smooth, its purpose is to reduce the ratio of parent metal melting into the weld metal, in order to reduce the carbon content in the weld seam, to prevent the crack.
Four, the welding process parameters
Because the parent metal melting into the first layer of weld metal in the proportion of up to 30%, so the first layer seam welding, should try to use small current, welding speed slow, to reduce the parent metal penetration.
Five, the heat treatment after welding
Best butt welding pieces immediately eliminate stress after welding heat treatment, especially for the large thickness of welding, high rigid structure and harsh conditions (dynamic load and impact load) even so is the work of the weldment.Eliminating stress tempering temperature is 600 ~ 650 ℃.
If unable to eliminate stress after welding, heat treatment shall be carried out immediately after heat treatment.