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Common sense of vacuum heat treatment

When disposing of titanium alloy in vacuum furnace, it is not suitable to use nitrogen as a cooling gas, because titanium and nitrogen react at high temperature, forming golden yellow titanium nitride.

2021

09-15

Technological steps of ultra-cryogenic treatment equipment

Ultra-cryogenic treatment technology, the treatment process is the key to determine the treatment effect. The key influencing factors of the cryogenic treatment process mainly include: cryogenic treatment method, temperature ramp speed, pre-tempering treatment or post-tempering treatment, holding time, cryogenic times, etc.

2021

09-15

How to select the appropriate number of tubes for air heat exchangers

The number of air heat exchanger passes selected depends mainly on the allowable pipe pressure drop and the temperature range variation of the fluid. The tubing process allows for a wide range of pressure drops and fluid temperature variations, and multiple pipe passes are available. When the single-phase fluid is cooled, the flow rate is increased as much as possible under the condition of meeting the allowable pressure drop, the general liquid flow rate is between 0.5-1.5m/s, and the gas flow rate is about 5-10kg/(㎡.s). It is advantageous for the fluid in the tube to be in a turbulent state, so it is more appropriate to choose more than two pipe strokes. For condensation processes, if the logarithmic mean temperature difference correction factor is less than 0.8, a two-tube or multi-tube pass should be considered.

2020

02-25

Several methods to improve the total heat transfer coefficient of finned tube heat exchanger

When the heat transfer film coefficient on the two sides of the heat transfer surface is very different, it is suitable to use a finned tube heat exchanger, because at this time, the smaller side becomes the main aspect of controlling heat transfer. When designing a finned tube heat exchanger, the heat transfer coefficient on the smaller side should be increased as much as possible. The membrane coefficients on both sides are roughly equal, and the main ones are more favorable.

2020

02-13

Heat treatment and quenching process of Aluminum Alloy

The purpose of this process is to make a large number of usable hardening elements such as copper, magnesium, zinc or polyester solids into solid solutions, which must be kept at a high temperature of 535 degrees - 550 degrees for a sufficient time of 6-8 hours to obtain a homogeneous solid solution. 1. Aluminum alloy solid solution temperature, aluminum alloy wheel solid solution point is 530 degrees, dissolution point is 555 degrees. At this temperature, it begins to melt into molten aluminum.

2020

02-13

Principle of vacuum gas nitriding

Gas nitriding generally uses anhydrous ammonia (or ammonia + hydrogen, or ammonia + nitrogen) as the nitrogen supply medium. The entire nitriding process can be divided into three stages.

2020

02-12

Some introduction of vacuum nitriding treatment

The elements aluminum, chromium, vanadium and molybdenum in traditional alloy steels are very helpful for nitriding. When these elements come into contact with primary nitrogen atoms, these elements form stable nitride at the nitriding temperature. In particular, molybdenum is used not only as a nitride-forming element, but also as a brittle property that occurs when the nitriding temperature decreases.

2020

02-12

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