Analysis of the hottest problems about forgings

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About the analysis of forging products

forging products are also like steel products in recent years. Generally, carbon steel parts, especially small parts of 200kg, have many manufacturers, with some surplus. Medium weight forgings, 0.5t-10t forgings are mostly shaft, flange, tube plate, ring gear, etc., which are gradually increasing in China, and the market competition is becoming increasingly fierce. The LCD display measurement system used in the universal experimental model of medium weight forging materials is relatively miscellaneous, which often includes low-alloy steel: such as 16Mn, 20MnMo, 35CrMo; Medium carbon alloy structural steel, such as 40Cr, 40crni, 5CrMnMo, 3Cr2W8, 34CrNi3Mo, etc., stainless steel 2Cr13, 3Cr13, 4Cr13, 1Cr18Ni9Ti, 0Cr17Ni12Mo2, 0cr17ni14mo2, 0Cr19Ni9; High carbon alloy steels such as 65Mn, 60crnimo, 60simnmo, etc. the problems of these forgings are: the forgings fail to pass the flaw detection after forging, which often shows that there is no bottom wave in the flaw detection, or there are internal pores, porosity, inclusions, cracks and other defects. Some can be repaired by heat treatment or repair welding, but sometimes the internal defects are serious and cannot be repaired, resulting in waste products, and sometimes the manufacturer negotiates with the user for degradation

large forgings above 20t, such as rollers, turbine rotors, marine low-speed diesel engine crankshafts, marine transmission shafts, reactor casings, etc. There are few manufacturers of such large forgings, and there are also quality problems. For example, the large roll produced by a factory falls off when used, and sometimes the defects in the steel ingot are brought into the forgings. This is a steel-making problem. The problem with medium-sized forgings is that there is a rare shortage of manufacturers producing steel ingots for forging. For example, there are few enterprises producing stainless steel ingots above 5T in China, making the forging factories have no choice, It is also easy to cause activity monopoly, which is also a very important consideration factor due to its centralized improvement of processing characteristics and design flexibility. Moreover, steel mills do not produce ingots for forging. General carbon steel or medium and low carbon alloy steel ingots can also be produced by several domestic heavy machinery plants, but stainless steel is difficult. Domestic heavy machinery plants do not have AOD furnaces or VOD furnaces for stainless steel. Therefore, it is suggested that qualified heavy machinery plants add AOD furnaces to alleviate the contradiction of stainless steel ingots, which is not only in the Chinese market

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