Stainless Steel Sleeve Preventive Measures
Preventive measures against crack, shrinkage hole, and loosening of stainless steel sleeve
Preventive measures for cracks of stainless steel sleeve
(1) Check Cutting
Strict inspection should be carried out on the operating system to cut the existence of form and position influencing factors so that the centerline of the die tube is in line with the horizontal line of the working platform.
(2) Select proper coating
Select proper stainless steel sleeve centrifugal casting coating (e.g. GCM-3 coating) and adopt the correct spraying method. It is advisable to control the coating thickness to 3-5 mm in general.
(3) Control the pouring temperature of pipe mould
The pipe mold is poured at 250-350 C. This measure can reduce the temperature difference between coating and liquid metal of pipe mold and pipe mold, reduce the compound crack caused by heat-induced cracking or warping and peeling of coating, resulting in scarring on the outer surface of centrifugal casting, and prolong the service life of pipe mold.
(4) pouring process
The pouring process of stainless steel sleeve is fast-medium-slow. Quick pouring is generally about 1/5 of the total amount; slow pouring is about 1/5 of the total amount; pouring time is about 1/5 of the total running time. For centrifugal castings with a mass of < 1 000 kg, a “fast-slow” pouring process of steel sleeve is enough.
(5) reasonable rotating speed
Adopt a reasonable rotating speed process. For products such as coiler sleeve, strong vibration and noise will occur in the whole equipment system in the middle and later stages of casting solidification if the first speed process of Figure 1a is adopted. This vibration is the catalyst for cracking.
Prevent Loosening and shrinkage
Preventive measures for loosening and shrinkage of stainless steel sleeve
(1) Control speed
Determine the reasonable maximum speed and control the working time of the second speed.
(2) Control temperature
Control the pouring temperature of molten steel. Generally speaking, the centrifugal casting temperature is 20-30 degrees lower than the sand casting temperature. Because the temperature is too high, also to increasing the liquid metal used for feeding the working time at the same speed, it will also affect the results of the whole reasonable process.
(3) Use internal treatment agent
Use an internal treatment agent with a suitable melting point. After pouring, it is put in proportion to 0.5% of the casting quality. Also to suction, slag collection, and thermal insulation, its main function is to reduce the heat loss carried by the “whirlwind”.