The cast iron welding penetration method of manufacturing materials in the automotive industry occupies a large proportion. For example, the gearbox of the automobile gearbox, the flywheel of the car, the penetration analysis system of various seats of the car and other connectors are used this method. Most of the cast iron parts are high-precision, expensive basic parts, penetration detection system microscope Such as cylinder block, cylinder head, transmission housing, etc. Welding penetration measuring instrument During the manufacture and use of cast iron parts, the welding penetration analyzer often has cracks, porosity, damage, etc. According to statistics, under normal use of the welding penetration measurement system, when such parts reach the wear limit, the dimensional change is only 0.08% to 0.40%, and the quality loss of the weld penetration depth measuring instrument is only 0.1% to 1.8%. Depth measurement instrument microscopes scrap parts at this time, which is undoubtedly very wasteful. Therefore, it is necessary to research and use advanced repair experience to reasonably repair cast iron parts. Welding is a very effective method of repairing cast iron parts.
Cast iron has high carbon content, many impurities, and has the characteristics of low plasticity, poor weldability, and sensitivity to cooling speed. After the weld penetration of the pressure vessel is detected, white mouth structure and cracks are prone to occur after welding. In order to improve the welding quality of cast iron parts, the welding penetration detection technology can adopt the following methods.
1. Hot welding
Before welding, preheat the whole or part of the workpiece to 600 ~ 700 ℃, the welding penetration detection example is not less than 400 ℃ during the repair welding process, and slowly cool to room temperature after welding. The hot welding method can effectively reduce the temperature difference of the welded joint, analyze the welding penetration defect to reduce the stress, and at the same time can improve the plasticity of the casting and prevent the appearance of white mouth structure and cracks.
Commonly used welding methods are gas welding and electrode arc welding. Welding penetration detector gas welding commonly uses cast iron gas welding wire, such as HS401 or HS402, with flux CJ201 to remove oxides. Boiler welding penetration analysis. Gas welding preheating method is suitable for repair welding of small and medium-sized thin-walled parts. Welding electrode arc welding uses cast iron core cast iron electrode Z248 or steel core cast iron electrode Z208. Welding penetration size inspection and measurement This method is mainly used for the penetration depth detection system of cast iron parts with large repair thickness (more than 10mm). The welding equipment of the hot welding method mainly includes a heating furnace, a welding torch, an electric furnace for measuring the welding penetration of a pressure vessel (oil furnace or hearth furnace), etc.
2. Cold welding
In this method, the workpiece is not preheated before welding. The penetration depth of the welded butt joint or the preheating temperature does not exceed 300 ° C. Commonly used electrode arc welding for cold welding of cast iron. According to the requirements of cast iron workpieces, different welding depth measuring instruments can be selected with different cast iron electrodes. Video welding penetration depth measuring instruments such as repair welding are generally made of gray cast iron parts. Z100 welding rods are used for non-machined surfaces. Zll6 is used for repairing high strength gray cast iron and ductile iron parts. Or Z117 welding rod. The welding equipment of the cold penetration method of the welding penetration detection system is a common arc welding equipment.
3. Heating reduction welding method
This method does not heat the weldment in advance, and the pipeline penetration analysis and detection system heats the "heat reduction zone" of the weldment before and during welding. The detection of the hot plate welding of
Automobile Parts does not hinder the shrinkage of the weld. Thereby reducing internal stress and avoiding cracks. One or more heating relief areas can be selected for the welding depth detection of the seat connector of automobile parts and components, and the selection principles are:
1) The weld penetration depth measuring instrument should be the part that hinders the expansion of the weld. When this part is heated and cooled, it is possible to obtain free thermal expansion and cold shrinkage of the weld seam.
2) Weld penetration testing should be performed at locations with little contact with other locations and with greater strength.
3) The deformation of itself should not have a great influence on other parts, so as not to damage other parts due to its deformation.
September 30, 2021
