Welding basics quiz, see if you know it all?

Basic knowledge 1. What is welding? A: welding is the process by which two or more materials (the same or different) are combined to form a permanent bond between atoms by heating or pressurizing or both. 2. What is arc? A: by the welding power supply, between the two poles to produce a strong and lasting gas discharge phenomenon – called arc. < 1 > according to the current type can be divided into: ac arc, dc arc and pulse arc. < 2 > according to the state of the arc can be divided into: free arc and compression arc (such as plasma arc). < 3 > according to the electrode material can be divided into: melting electrode arc and non-melting electrode arc. 3. What is base material? A: the metal being welded is called the base metal. 4. What is a melt drop? A: a liquid metal droplet that melts at the end of the wire and passes into the pool is called a droplet. 5. What is a molten pool? A: the part of liquid metal with a certain geometric shape formed on the welding part is called the molten pool. 6. What is weld? Answer: the combined part formed in the welded part after welding. 7. What is weld metal? Answer: the part of metal formed by solidification of molten base metal and filler metal (wire, electrode, etc.). What is a protective gas? A: a gas used in welding to protect metal droplets and pools from harmful gases (hydrogen, oxygen, nitrogen). 9. What is welding? Answer: all kinds of welding methods, welding materials, welding process and welding equipment and their basic theory of the general name – called welding technology. 10. What is welding process? What does it have? A: a complete set of process procedures and technical requirements in the welding process. The content includes: welding method, pre-welding preparation, assembly, welding materials, welding equipment, welding sequence, welding operation, welding process parameters and post-welding treatment. What is CO2 welding? Answer: use purity > 99.98% of CO2 to do the gas protection gas welding – called CO2 welding. 12. What is MAG welding? A: use a mixture of 75–95% Ar + 25– 5% CO2, (standard ratio: 80%Ar + 20%CO2) to do a shielded gas welding of the molten electrode of shielded gas — called MAG welding. 13. What is MIG welding? A: welding non-ferrous metals such as aluminum and aluminum alloy, copper and copper alloy with fused electrode gas protection with high purity argon Ar≥ 99.99% as protective gas. The process of solid stainless steel wire welding with 98% Ar + 2%O2 or 95%Ar + 5%CO2 as protective gas is called MIG welding. < 3 > FGD with helium + argon inert mixture. What is TIG welding? A: inert gas shielded arc welding (TIG welding) with pure or activated tungsten (thorium tungsten, cerium tungsten, zirconium tungsten, lanthanum tungsten) as the non-melting electrode. 15. What is SMAW welding? Answer: manual operation of welding rod welding arc welding method. 16. What is carbon arc gouging? A: a surface machining method that USES carbon rods as electrodes to generate an arc between the workpiece and blow the molten metal away with compressed air (pressure 0.5-0.7 Mpa). Commonly used for weld root cleaning, planing groove, repair defects. 17. Why is CO2 welding more efficient than electrode arc welding? Answer: < 1 > CO2 welding is 1-3 times higher than the melting speed and melting coefficient of electrode arc welding; The groove section of < 2 > is 50% less than that of the welding electrode, and the amount of deposited metal is 1/2 less. < 3 > auxiliary time is 50% of the electrode arc welding. Compared with electrode arc welding, the efficiency of CO2 welding is improved by 2.02–3.88 times 18. Why is the quality of CO2 welding joint better than that of arc welding joint? Answer: CO2 weld heat affected zone is small, welding deformation is small; The hydrogen content of CO2 weld is low (≤ 1.6ml /100g), and the porosity and crack tendency are small. The CO2 weld is well formed, with less surface and internal defects, and the qualified rate of flaw detection is higher than that of electrode arc welding. 19. Why is CO2 welding cheaper than electrode arc welding? Answer: < 1 > groove cross-sectional area reduces 36-54%, saving filling metal amount; < 2 > reduces power consumption by 65.4%; Compared with welding electrode arc welding, the working rate of > equipment can be reduced by 67-80%, and the cost can be reduced by 20-40%. < 4 > reduce labor cost and labor cost, and reduce the cost by 10-16%; < 5 > saves auxiliary labor, auxiliary material consumption and deformation correction costs; Combined with the five items,CO2 welding can reduce the total cost of welding by 39.6-78.7%, with an average reduction of 59%. 20. What is a low-frequency pulse? Which welds are applicable? A: a pulse arc with a pulse frequency between 0.5 and 30Hz is called low-frequency pulse welding. It is mainly used for TIG welding of stainless steel, steel, titanium and other nonferrous metals. What is an intermediate frequency pulse? Which welds are applicable? A: pulse arcs with pulse frequency between 30 and 500Hz are called if pulse welding. Due to arc compression effect, concentrated arc and good stiffness, it is mainly used for TIG welding of thin stainless steel, steel, titanium and other non-ferrous metals and MIG welding of stainless steel, aluminum and aluminum alloy. 23. Why spatter in CO2 welding? Answer: the welding wire end of the drop and the pool short circuit contact (short circuit transition), due to strong overheating and magnetic contraction of the drop burst, resulting in splash. The output reactor and waveform control of CO2 welder can minimize spatter. 23. Why can MIG/MAG high-current welding achieve jet transition without splash? Answer: when MIG/MAG welding, all kinds of metals have a short circuit transition to the critical flow value of jet transition (such as: 1.2 carbon steel, stainless steel wire, current I≥ 260-280a), at this time the arc is jet transition state, to achieve no splash welding. 24. Why does MIG/MAG small current welding need pulsed power to achieve jet transition without splash? Answer: MIG/MAG welding, the welding current is lower than the critical current value, using pulse power supply, its pulse current is greater than the critical current value, arc transition state, can also be a jet spray welding is realized (such as: use the panasonic hf-solvated AG2 / GE2 pulse MIG/MAG welding machine, phi 1.2 carbon steel, stainless steel, aluminum and aluminum alloy welding wire has been implemented in current I p 80 a pulse shot transition, its pulse current Ip 350 a or higher).铜焊丝,Copper Welding Rods,铝焊丝,aluminium welding wire,镍焊条,Nickel electrode,药皮焊条,Flux Coated Brazing Welding Rods