1. What is welding material? What is included?
A: Welding materials include welding rods, welding wire, flux, gas, electrodes, gaskets, etc.
2. What is welding wire?
Answer: As a filler metal during welding, it is also used to conduct conductive wire—called wire. Divided into solid wire and flux cored wire. Commonly used solid wire type: ER50-6 (brand: H08Mn2SiA).
3. Why is the impact toughness of MAG welded joints higher than that of CO2 welded joints?
Answer: When MAG is welded, the reactive gas is only 20%, the transition coefficient of the alloying elements in the welding wire is high, and the impact toughness of the weld is high. The CO2 welding active gas is 100%, and the manganese and silicon alloy elements in the welding wire are jointly deoxidized. The transition coefficient of the alloy elements is slightly lower, and the impact toughness of the weld is not as high as that of the MAG welding. For example, Tangshan Kobelco MG-51T welding wire (equivalent to ER50-6) its normal temperature impact toughness value: MAG: 160J; CO2: 110J.
4. What is the flux cored wire?
Answer: A wire that is drawn from a thin steel strip into a circular steel tube and filled with a certain amount of powder.
5. Why is the flux-cored wire protected by CO2 gas?
Answer: There are two types of flux cored wire according to the protection method: the core gas shielded welding wire and the core self-protecting welding wire. The core gas shielded welding wire is generally protected by CO2 gas, which belongs to the joint protection form of gas and slag, has good weld formation and high comprehensive mechanical performance.
6. Why does the surface of the flux-cored wire weld indented?
Answer: Because the flux-cored wire is a tubular welding wire rolled from a thin steel strip, it belongs to a seamed welding wire; the moisture in the air will invade the core through the gap, and the flux is wet (cannot be dried), causing the weld to have indented pores.
7. Why are there technical requirements for the purity of CO2 gas?
Answer: Generally, CO2 gas is a by-product of chemical production. The purity is only about 99.6%. It contains trace impurities and moisture, which will cause defects such as pores in the weld. The important products for welding must use gas with CO2 purity ≥99.8%, less weld porosity, low hydrogen content and good crack resistance.
8. Why are there higher technical requirements for argon purity?
A: There are currently three types of argon on the market: argon (purity of about 99.6%), pure argon (purity of about 99.9%), high purity argon (purity of 99.99%), the first two weldable carbon steels and stainless steels; High-purity argon must be used for non-ferrous metals such as aluminum alloy, titanium and titanium alloy; it is not possible to weld the weld and heat-affected zone.
9. Why are TIG welding nozzles available in various sizes?
Answer: There are five kinds of nozzles of No. 4-8, and No. 4-5 nozzles can be used for welding carbon steel. No. 6-7 nozzles should be used for welding stainless steel and aluminum and aluminum alloy to strengthen the protection range of weld and heat affected zone. . Welded titanium and titanium alloys and other non-ferrous metals should use larger nozzles No. 7-8 to prevent oxidation and heat affected zone from being oxidized.
10. What is an acid electrode?
A: The electrode contains a large amount of acid oxide electrode, such as junction 422 (E4303), knot 502 (E5003) and other AC and DC welding electrodes.
11. What is a basic electrode?
A: The electrode contains a large amount of alkaline oxide and fluoride containing electrode, such as knot 507 (E5015), knot 506 (E5016) and other welding electrodes.
12. What is a cellulose type (for downright welding) electrode?
A: The electrode contains a large amount of organic electrodes, and the pipe and thin plate structure are used for vertical welding.
<1> For example, E6010 (equivalent to E4310, J425G) is suitable for bottom welding, heat welding, and filler welding.
<2> E8010 (equivalent to E5511, J555) is suitable for heat welding, filler welding, and cover welding.
Generally, the low-hydrogen down-welding electrode is used for surface welding; E7048 (equivalent to J506X) has a neat and beautiful appearance.
13. Why should the welding rod be strictly dried before welding?
Answer: The welding rod tends to deteriorate the process performance due to moisture absorption, resulting in unstable arc, increased spatter, and defects such as pores and cracks. Therefore, the electrode must be strictly dried before use. Generally, the drying temperature of the acid electrode is 150-200 ° C, the time is 1 hour; the drying temperature of the alkaline electrode is 350-400 ° C, the time is 1--2 hours, and the incubator is placed at 100--150 ° C after drying. Inside, use it with you.