Carbon steel pump equipment parts repair methods

Chemical pump parts used in a wide range of steel materials, the welding of a great difference. In the case of carbon steel, the higher the carbon content in the steel, the greater the propensity for cracks to occur during welding and the poorer the weldability. The more stringent the requirements are for welding technology.

1 low carbon steel parts welding

w (C) ≤0.25% carbon steel is mild steel, good weldability. Bonding welding generally do not need to take special technological measures, the choice of general J422-type electrode can be satisfied with the results. Only in special cases, for example, parts stiffness is very large, when the weld is very large or low temperature welding cracks may occur, pay attention to the selection of high quality welding rod, in order to enhance the crack resistance of weld metal, while using a reasonable The welding process to reduce welding stress.

2, high carbon steel parts repair welding

Carbon steel having w (C) of 0.25% to 0.50% is medium-carbon steel, and w (C) of high-carbon steel is not less than 0.50%. With the increase of carbon in steel, the sensitivity of welded joints to cracks increases accordingly. The cracks are mainly caused by the hot cracks in the weld, the cold cracks caused by the low-plasticity and hard-tissue caused by the rapid cooling in the heat-affected zone, and the hydrogen induced cracks mainly caused by the infiltration of hydrogen at the root of the weld.

In order to prevent cracks in medium and high carbon steel parts welding process can take the following measures:

1) to improve the welding heat cycle, reducing the cooling rate of the main measures for the preheating before welding. It can reduce the hardness of the heat affected zone, and reduce residual stress and deformation, thus effectively preventing cracks in the weld and heat affected zone.

The degree of carbon steel preheating depends on the amount of carbon content and part stiffness, you can roughly the following empirical formula to estimate the pre-heated electrode arc welding temperature:

Preheat temperature (° C) = 500 (CE-0.11) + 0.4t (5-1)

Where CE --- carbon equivalent of steel (%) ,: CE = c + (Mn + si) / 4

t-- part thickness (mm).

This formula is mainly used for parts thickness t ≥ 20mm) situation. Second, multi-layer welding can also be used to improve thermal cycling. Each seam on the weld after a preheating can play a role, but also on the role of a slow cooling before the weld, which played a good role in preventing cracks. Post-welding slow cooling and stress relief treatment play a good role in the crack.

2) Select the appropriate electrode as far as possible the selection of low hydrogen electrode to enhance the crack resistance of the weld, the electrode should be dried and placed in the insulation tube, with the use of take. The intensity of the electrode should be consistent with the base metal.

3) to strengthen the cleaning work of the welding area completely eliminate any possible source of hydrogen into the weld, such as oil, water, rust and other impurities.

4) Try to reduce the proportion of base metal into the weld, such as open V-shaped groove, the first layer of welding with a small current welding, etc. are all effective methods. However, care must be taken to melt the parent metal to avoid defects such as slag inclusions and incomplete penetration.

The thick film heating technology is new type of heating technology which is developed mainly by DuPont and Heraeus in 1990s. They developed the electronic paste can be used on the stainless steel substrate firstly. Using screen printing technology to print and sinter dielectric layer, resistance layer, silver conductor layer and isolation glazes protective layer on the stainless steel, so as to obtain a new type of Heating Element

Thick film heater can successfully replace Traditional Electric Heating Tubes/Elements, change their structures and performance completely, which can reduce energy consumption, increase energy utilization and save space.

Thick Film Heater Elements are widely applied in Instant Hot Water Dispenser, instant boiling water heaters, sous vide, coffee maker, electric heating water faucet, instant water flow heater under sink, diswasher, washing machine,formula dispenser, vending machine, industrial water flow heater, circulating heating of swimming pool water, industrial equipments etc.

Heater Category By Application

Heater Category by Application,Heater Category,Small size heater,electric tubular heater

XINXIANG JIEDA PRECISION ELECTRONICS CO.,LTD , https://www.gidaheater.com