Key points in the process of high chromium steel ball casting

2018-02-08
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Generally speaking, the end customers of the company's wear resistant materials mainly include mining, cement, construction and power plant. The performance of the wear resistant steel ball is related to the cost and benefit of the end customer. At present, with the wear resistant casting industry, the company's technology level is higher, the higher performance and higher efficiency of the high chromium steel ball to replace the low efficiency of steel ball.

High chromium steel, is in the original chemical components added trace of gold, chromium, manganese etc. metal elements, the use of advanced anhydrous resin sand molding, oil quenching heat treatment technology, produced good toughness, high wear resistance of high performance wear resistant steel ball. This kind of product has good performance, can prolong the use cycle, reduce the production cost and labor cost of wear resistant material enterprises.

Here we analyze several key points of high chromium steel ball casting process:

1 high chromium steel ball casting, casting temperature is low, it is advantageous to refine the dendritic and eutectic structure, but also to avoid the occurrence of excessive temperature caused by excessive shrinkage and surface adhesive sand and other defects. Pouring temperature generally around than the liquidus (1290 to 1350~C) high 55, light a small piece of general control in 1380 to 1420~C, wall thickness 100ram above thick pieces of control in 1350 to 1400~C.

2 high chromium cast iron with the same amount of shrinkage and cast steel, the shape of the line shrinkage rate can be calculated by 2% 1.8%. In the sand production, the riser size can be calculated according to the provisions of the carbon steel, and pouring system according to grey cast iron calculation, but need to by 20% ~ 30% increase in the cross-sectional area. Riser choice should pay attention to two aspects: one is to ensure the casting belt (the use of the site) the quality; the second is to try to improve the rate of finished products of the castings.

3. High chromium cast iron casting performance is poor, its thermal conductivity is low, poor plasticity, high shrinkage and hot crack and cold cracking tendency, in high chromium steel casting process to combine the characteristics of cast steel and cast iron, we must give full attention to the casting of the feeding problem, its principle and cast steel pieces of the same (with riser and chill and follow the principle of sequential solidification). Due to the high chromium content in high chromium steel ball, it is easy to be in the surface of the iron liquid, so it seems that the liquid flow is poor, but it is in fact a good flow.

4 because of the high chromium casting riser is not easy to be removed, thus modeling in the form of riser should use side riser or knock off.

5. High chromium steel ball casting, modeling should be used water glass sand and other high strength and permeability of sand, paint should be with high refractoriness, high alumina or magnesia powder and alcohol mixing. In addition, in order to obtain the fine grain structure and the surface quality, the metal mould casting is also widely used in the case of the casting shape is not too complicated.

6 should pay attention not to let the casting appear blocked contraction, lest cause cracking. Casting cracking caused by in addition, after pouring out of the box temperature too high is also very easy, 540 DEG C under slow cooling is necessary, should make casting in the mold is cooled sufficiently, and then out of the box sand cleaning, or out of the box after the first not clear sand pile in together (casting, casting run system, etc.) around the dry sand slow cooling. Out of the box surrounding environment must be kept dry, not wet with water, otherwise easily cause casting crack.Generally speaking, the end customers of the company's wear resistant materials mainly include mining, cement, construction and power plant. The performance of the wear resistant steel ball is related to the cost and benefit of the end customer. At present, with the wear resistant casting industry, the company's technology level is higher, the higher performance and higher efficiency of the high chromium steel ball to replace the low efficiency of steel ball.

High chromium steel, is in the original chemical components added trace of gold, chromium, manganese etc. metal elements, the use of advanced anhydrous resin sand molding, oil quenching heat treatment technology, produced good toughness, high wear resistance of high performance wear resistant steel ball. This kind of product has good performance, can prolong the use cycle, reduce the production cost and labor cost of wear resistant material enterprises.

Here we analyze several key points of high chromium steel ball casting process:

1 high chromium steel ball casting, casting temperature is low, it is advantageous to refine the dendritic and eutectic structure, but also to avoid the occurrence of excessive temperature caused by excessive shrinkage and surface adhesive sand and other defects. Pouring temperature generally around than the liquidus (1290 to 1350~C) high 55, light a small piece of general control in 1380 to 1420~C, wall thickness 100ram above thick pieces of control in 1350 to 1400~C.

2 high chromium cast iron with the same amount of shrinkage and cast steel, the shape of the line shrinkage rate can be calculated by 2% 1.8%. In the sand production, the riser size can be calculated according to the provisions of the carbon steel, and pouring system according to grey cast iron calculation, but need to by 20% ~ 30% increase in the cross-sectional area. Riser choice should pay attention to two aspects: one is to ensure the casting belt (the use of the site) the quality; the second is to try to improve the rate of finished products of the castings.

3. High chromium cast iron casting performance is poor, its thermal conductivity is low, poor plasticity, high shrinkage and hot crack and cold cracking tendency, in high chromium steel casting process to combine the characteristics of cast steel and cast iron, we must give full attention to the casting of the feeding problem, its principle and cast steel pieces of the same (with riser and chill and follow the principle of sequential solidification). Due to the high chromium content in high chromium steel ball, it is easy to be in the surface of the iron liquid, so it seems that the liquid flow is poor, but it is in fact a good flow.

4 because of the high chromium casting riser is not easy to be removed, thus modeling in the form of riser should use side riser or knock off.

5. High chromium steel ball casting, modeling should be used water glass sand and other high strength and permeability of sand, paint should be with high refractoriness, high alumina or magnesia powder and alcohol mixing. In addition, in order to obtain the fine grain structure and the surface quality, the metal mould casting is also widely used in the case of the casting shape is not too complicated.

6 should pay attention not to let the casting appear blocked contraction, lest cause cracking. Casting cracking caused by in addition, after pouring out of the box temperature too high is also very easy, 540 DEG C under slow cooling is necessary, should make casting in the mold is cooled sufficiently, and then out of the box sand cleaning, or out of the box after the first not clear sand pile in together (casting, casting run system, etc.) around the dry sand slow cooling. Out of the box surrounding environment must be kept dry, not wet with water, otherwise easily cause casting crack.