Cast tin bronze is a commonly used wear-resistant anticorrosive material in the mechanical industry, which has good dry friction performance. It is called wear-resistant "copper alloy", which is usually used to process wear-resistant parts such as shaft sleeve, bearing, bearing, gear, worm gear and guide plate. Centrifugal casting can obtain dense castings, but there are many factors affecting centrifugal casting, if improper control will repeatedly produce some difficult to prevent the defects, we must take effective process measures to prevent the generation of these defects. Based on many years of production experience, the centrifugal casting process of tin bronze jacket is introduced in this paper.

Smelting process: The charge must be oiling and rusting to keep clean, add charcoal or homemade covering agent at the bottom of the electric furnace, add the amount to cover the surface of the copper liquid is appropriate, electric preheating 10 ~ 15min, and then add 95% electrolytic copper (reserve 5% electrolytic copper to adjust the temperature of the copper liquid in the later smelting period), when the temperature of the copper liquid rises to 1150 ~ 1200℃, With 2/3 phosphorus copper (add total weight of copper liquid 014% ~ 016%) alloy pre-deoxidation, at this time with graphite rod or coated with graphite coating iron rod stir copper liquid, then add after preheating (200℃ or so) pure zinc plate, pure lead plate and pure tin ingot, fully stirred temperature to about 1250℃, Add the remaining 1/3 phosphorus copper alloy for final deoxidation and refining treatment, at this time stationary 3 ~ 5min to make the alloy liquid fully slag back (this process is indispensable).

Pre-furnace inspection

The method of pre-furnace inspection is very simple, but very important and effective, should not be omitted. Molten alloy first pouring gas sample (Φ50 ~ 30mm×50mm inverted table sand sample or metal sample), with a board to scrape the surface of the sample oxide skin, see the change of the surface, if the sample surface concave, the bottom has a slight tear, indicating that deoxygenation thoroughly, alloy liquid qualified; If the sample surface is flat or convex, indicating that deoxygenation degassing is not good, alloy liquid is not qualified, must be re-added appropriate amount of phosphorus copper deoxygenation degassing or slag removal. After deaeration qualified alloy liquid pouring corner sample (R10mm×120mm semi-circular strip type), the sample cooling to about 300℃ (sample surface just turned black) quenching, and then break the sample to see the macro structure of the fracture, qualified fracture smooth is earth gray, fine organization, no segregation and slag inclusion, breaking Angle between 30° ~ 75°, Indicates that the mechanical properties of the material are qualified, and the casting can be poured. If the breaking Angle is too large, alloying elements (Sn, P, etc.) can be added to improve the strength of the alloy; If the bending Angle is too small, appropriate amount of electrolytic copper or pure zinc can be added to improve the toughness of the alloy. If the fracture grain is coarse and slightly red brick, indicating that the deoxidation is not complete, phosphorus copper should be added after the thorough deoxidation of the pre-furnace inspection, qualified before casting.

213 Casting process

Before casting, paint (zinc oxide and talc half, plus 1% ~ 3% rosin mixing) is brush in the centrifuge metal type to prevent sticky type, and then preheat the metal type to 300 ~ 350℃, and then slowly cool to the working temperature of 40 ~ 80℃ for pouring. At this time, the first centrifuge rotates smoothly, the first fast after slow, the first large after small pouring method is relatively fast pouring, pouring temperature according to the different alloy brand and changes, should be controlled in 1100 ~ 1200℃. If the metal type 2 sand coating centrifugal casting process is used, the sand coating layer should be thoroughly dried, and the pouring temperature is 30 ~ 50℃ lower than the metal type, which is controlled at 1050 ~ 1100℃. If the casting of ZCuSn10P1 alloy material with high phosphorus content, the casting temperature should be strictly controlled at 960 ~ 980℃, otherwise the casting will produce serious segregation and scrap.

After casting can not be stopped immediately, should continue to rotate the centrifuge, rotation time according to the wall thickness of the casting. According to production experience, the empirical formula of the relationship between the continuous centrifuge rotation time and the wall thickness of tin bronze castings after pouring is as follows:

t=μ · δ, t -- continuous rotation time,min

δ -- casting wall thickness,mm

μ -- factor,μ=0115 ~ 0120

The lower limit of μ is taken for metal type centrifugal casting, and the upper limit of μ is taken for metal type 2 sand coated centrifugal casting. The upper limit of μ is taken when the casting wall thickness is <20mm, and the lower limit of μ is taken when the casting wall thickness is >30mm.

Our company also specializes in the production of various specifications of large tin bronze copper sleeve, tin bronze matrix graphite copper sleeve, copper worm gear, copper nut, copper slide and other tin bronze products, the company continues to improve, and constantly meet customer requirements, welcome to centrifugal casting production drawings.