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How To Choose The Correct Welding Rod

Apr 16, 2020

The consideration factors are the selection principles of the physical, chemical properties and chemical composition of the weldment:

(1) According to the equivalent strength point of view, choose the electrode that meets the mechanical properties of the base material, or the electrode that combines the mechanical properties of the base material, or the weldability of the base material, and use a non-strength electrode with good weldability, but consider welding Seam structure type to meet the requirements of equal strength and rigidity

(2) The alloy composition meets or is close to the base metal

(3) When the base metal contains high levels of harmful impurities such as carbon, sulfur, and phosphorus, the electrode with good crack resistance and porosity resistance should be selected. It is recommended to use titanium oxide calcium type, and ilmenite type electrodes. If it cannot be solved, Optional low-hydrogen electrode

2. The selection factors are the working conditions and performance of the weldment:

(1) In the case of dynamic load and impact load, in addition to ensuring strength, there are higher requirements for impact toughness and uniformity of elongation. Low hydrogen, titanium calcium and iron oxide electrodes should be selected in sequence.

(2) For those in contact with corrosive media, the appropriate stainless steel electrode must be selected according to the type of media, concentration, operating temperature, and whether it is general corrosion or intergranular corrosion.

3. When working under wear conditions, it should be distinguished whether it is general or impact wear, whether it is wear at normal temperature or a high temperature

(4) When working under very hot conditions, you should choose the corresponding electrode to ensure the mechanical properties of low temperature or high temperature

(3) Consideration factors: the complexity and stiffness of the beginning of the weldment geometry, the preparation of the welding groove and the welding location selection principles:

(1) For weldments with complex shapes or large thickness, the weld metal shrinks with great stress during cooling and is prone to cracks. Welding electrodes with strong crack resistance must be used, such as low hydrogen electrode high toughness electrode or iron oxide electrode

(2) Welding parts that cannot be turned over due to conditions must be selected with electrodes that can be welded in all positions

(3) For welding parts that are difficult to clean at the welding site, use acid electrodes that are highly oxidizable and insensitive to oxide scales and grease to avoid defects such as porosity

4. The consideration factor is the selection principle when applying the welding site equipment:

Where there is no DC welding machine, it is not advisable to use electrodes with limited DC power supply, but electrodes with AC and DC power supply should be used. Some steel materials (such as pearlite heat-resistant steel) need to eliminate heat treatment after welding, but are limited by equipment conditions (or Due to its own structural limitations) when heat treatment cannot be performed, a non-parent metal material electrode (such as austenitic stainless steel electrode) should be used instead of post-weld heat treatment

5. The selection factors for improving the welding process and protecting the health of workers are:

Where acid electrodes and alkaline electrodes can meet the requirements, try to use acid electrodes

6. Factors to consider: Principles for selecting labor productivity and economic rationality:

In the case of the same performance, you should try to choose an acid electrode with a lower price instead of an alkaline electrode. Among the acid electrodes, titanium type and titanium calcium type are expensive.According to the situation of mineral resources in China, they should be vigorously promoted