熱門關鍵詞：濟南彩鋼板 | 濟南復合板 | 濟南彩鋼瓦 | 濟南c型鋼 | 濟南鋼結構 |
Today, the manufacturer of metal clad plate will explain the heat treatment requirements of the composite plate:
In order to eliminate the residual stress of explosive composite interface, 1Cr18Ni9Ti / Q235A was heat treated at different temperature and holding time. The microhardness of the welding interface was measured for the samples with cladding thickness d f = 2mm and loading ratio r = 1.20. After the samples were treated at 550 ℃ for 1 h, the microhardness curve was not different from that at room temperature. However, the microhardness curves of the samples treated at 650 ℃ and 750 ℃ for one hour are obviously lower than those at room temperature, indicating that the heat treatment is effective.
Scanning electron microscope (SEM) was used to analyze the samples. The results showed whether the interface of the two sides of the module was diffused after heat treatment, that is to say, Q235A with chromium and nickel module and 1Cr18Ni9Ti with silicon and iron module. The diffusion degree has nothing to do with the heat treatment temperature, but has something to do with the sampling position: the farther away from the interface, the less the diffusion component content. It shows that the diffusion of components on both sides of the interface is generated by explosive welding itself, and has nothing to do with heat treatment. When the temperature is lower than 550 ℃, the peak value of carbon can not be seen even on the sub surface of stainless steel (see Fig. 1a). However, at 650 ℃, a small carbon peak can be seen in the transition zone far away from the interface (see Fig. 1b), which indicates that carbon in carbon steel has diffused to the transition zone of stainless steel, and the diffusion of carbon composition is related to the heat treatment temperature.
(a) 550℃不銹鋼二次表面，無碳峰(b) 650℃不銹鋼過渡區，有碳峰
(a) 550 ℃ stainless steel secondary surface, no carbon peak (b) 650 ℃ stainless steel transition zone, with carbon peak
The surface layer (near interface layer) of carbon steel treated at 550 ℃ has fibrous structure and many fine particles caused by serious deformation. The core structure is ferrite and pearlite. The second stage is the stainless steel interface point like tissue, and the heart is needle like tissue. However, the small particle structure of the near interface area of the carbon steel treated at 650 ℃ disappeared (indicating that decarburization may occur), and the grains became thicker. The core structure is still ferrite and pearlite, but the slip line caused by structural deformation has disappeared. There are a lot of small black particles on the interface of stainless steel, which may be formed after decarburization of chromium carbide particles. The surface metallography of carbon steel treated at 750 ℃ is similar to that of carbon steel treated at 650 ℃, and the loss range of small particles and the grain size increase in the near interface region. However, the iron core has been transformed into plate martensite + massive ferrite, and the transformation has been estimated. The surface of stainless steel and iron core are basically the same, 650 ℃.
In conclusion, when the heat treatment temperature is lower than 550 ℃, the microhardness of the near zone on both sides of the interface does not change, and Q235A steel is basically not decarburized. When the heat treatment temperature is higher than 650 ℃, the microhardness of Q235A steel decreases obviously, but decarburization still exists. Therefore, the heat treatment temperature is estimated to be about 600 ℃.
Whether the composite plate is heat treated or not, there is material diffusion on both sides of the interface. The diffusion degree is not related to the heat treatment temperature, but to the distance from the interface.