How to avoid pinhole of aluminum alloy investment casting
How to avoid pinhole of aluminum alloy investment casting
Q: I shop was mainly used for forging ZL104 aluminum alloy in air, but at the moment, the viscosity of liquid aluminum, the surface crust, forging shop, the quality of the pinhole of nearly two years subject always remains in the casting as pinhole. Without treatment. In addition to the big, thick big present shi kong pays amount of hydrogen in aluminum melt, besides is inversely proportional to the temperature outside, also more and more small and medium-sized pieces of riser root and processing end also with pressure and atmosphere humidity namely hydrogen partial pressure is inversely proportional to. Alloy presents the topic of pinhole out-of-tolerance. Many thanks for your advice of pinhole primary element and its content on the melt degree is big, the influence of silicon and copper reason is what?Are there any ways to avoid pinholes in aluminum alloy?Decreased melt degree, magnesium, hydrogen receipt. The experiment table state-owned 405 factory casting workshop fee L Yang Ming alloy composition differences occurred pinhole critical hydrogen content of the four O five factory iron foundry has been disambiguation FeiYang fellow: sample, ZL104 aluminum alloy type of hypoeutectic al-si alloy ZL104 aluminum alloy very easily the introduction letter from your workshop pinhole out-of-tolerance constitute a pinhole. Else, the topic of solidification rate is sensitive to constitute a pinhole, is indeed a crisis affecting the quality of cast aluminum. Has inevitably influence by sex, and heavy section ductile iron castings solidification slow than force in forging production process is complex, incur castings in the hot section of the pinhole pinhole is a tough one.
The forging stress of aluminium alloy cent is 3 kinds, what kind is apart?
(1) aluminum silicon alloy, also called silicon or silicon aluminium Ming. Outstanding casting function and wear-resisting function, small expansion coefficient, most species in the forging of aluminum alloy, alloy dosage the biggest, silicon content was 10% ~ 25%. The accident increased by 0.2% ~ 0.6% magnesium silicon aluminum alloy, widely used in layout, such as, cylinder block, to body and frame. Adding appropriate copper and magnesium, by accident can you improve the mechanical function and heat resistant alloy. This kind of alloy widely used in the manufacture of piston.
(2) aluminum-copper alloy, alloy containing copper 4.5%~5.3% has the best strengthening results, proper handling of manganese and titanium can significantly improve the strength and forging function at room temperature and high temperature.
(3) aluminum and magnesium alloy, minimum density (2.55 g/cm3), the intensity of the highest forged the mercy (355 mpa) aluminum alloy, including 12% magnesium, strengthen the result is the best. In the air and seawater erosion resistance of alloy function good, outstanding function of heald together to learn and at room temperature can be cutting, can be used to make the radar base, the plane had hatched pattern in box, propeller, lifting frame parts, such as can also be as a decoration material.
(4) aluminum zinc alloy, for improved function often intervene in silicon, magnesium, zinc is often referred to as the silicon aluminum. Under the precondition of forging, the alloy has a quenching influence, namely self hardening. Not can use, the heat treated to deteriorate after heat treatment, casting a higher intensity. After not change disposal, size remains the same, is often used to build mold, plate and equipment support, etc.).
