How to solve the problem of decarburization on the surface of 304 stainless steel pipe?

[guidebook] : With the development of stainless steel, the application of 304 stainless steel pipe becomes more and more extensive. In the actual application process, the appearance of 304 stainless steel tube will sometimes appear decarburization...

With the development of stainless steel, the application of 304 stainless steel pipe becomes more and more extensive. In the actual application process, the appearance of 304 stainless steel tube will sometimes appear decarburization phenomenon. When the appearance of decarburization exceeds a certain standard, it will be detrimental to the surface layer of carbon compounds as the consolidation phase and wear-resistant phase, so it will directly affect the performance of the application, and bring a certain degree of safety hazards to the application operation. So, 304 stainless steel pipe how to solve the problem of surface decarburization?

The stronger the oxidizing atmosphere of the pipe furnace gas, the higher the heating temperature, the longer the heat preservation moment stainless steel pipe is more likely to decarburize; the degree of decarburization is also related to the carbon content of the steel, usually higher carbon content of the steel is also easy to decarburize. In order to avoid this phenomenon, we suggest the following three aspects of control.

1, raw materials: should be selected from large manufacturers of positive material, although all 304 material, but the medium frequency furnace belongs to the waste recycling recycled steel, a variety of high impurity content, and different batches of carbon content in the original material can not be maintained consistently, and even in many cases the carbon content will be on the high side, which further promotes decarburization of the occurrences.

2, strict control of temperature and holding time: remove the moisture on the surface of the 304 stainless steel pipe by baking, and put the stainless steel welded pipe in the sleeve for indirect heating, so that it is easier to control the temperature change. And add appropriate charcoal in the sleeve to reduce the oxidizing atmosphere of the furnace gas and reduce the reaction rate of decarburization.

However, the charcoal can not be too much or directly added to the stainless steel welded pipe, otherwise the charcoal is burned and heated, it will increase the temperature of the stainless steel pipe, which will not only make it difficult to control the heating temperature, but also exacerbate the decarburization reaction, leading to the opposite effect. Heating length should also be strictly controlled, if it is at a high temperature for too long, will also lead to decarburization.

3, avoid lead dust pollution: many 304 stainless steel pipe made of components of the service life of the steel products related to the degree of surface decarburization. Because the decarburization and steel oxygenation is carried out at the same time, so as long as the thermal disposal process as much as possible to make the steel pipe less contact with the air can be achieved to improve the purpose of decarburization.

Overseas imports of stainless steel pipe decarburization layer of 0.04mm, the production process is as follows: the first lead tank steel wire austenitization effect, pre-heating of lead to 871 ℃, stainless steel products in the lead through the pipe, the success of austenitization, and then into the tank quenching, and then into the second lead tank tempering (482 ℃). Practice has proved that foreign enterprises use double lead tank oil quenching and tempering to dispose of steel wire for valve springs, it has obtained the desired effect.

The above is how to solve the problem of surface decarburization of 304 stainless steel pipe, the surface decarburization of steel pipe will affect the use of performance, and bring certain safety hazards. And solve the problem of pipe surface decarburization, in addition to selecting high-quality raw materials, but also from a technical point of view to deal with is the most basic way to solve the problem of decarburization of 304 stainless steel pipe appearance key in the heat treatment process, strict control of temperature, heating duration and avoid lead dust pollution, can effectively solve the problem of decarburization.