Also called steel screw thread sheath, screw set, mechanical equipment is one of the indispensable parts of hardware, wire Lo sets of mechanical equipment overall quality plays a vital role, so in the choice of steel wire Lo sets of material, need to focus on understanding and application conditions of thread sheath, this paper mainly introduces about thread the set of materials and the applicable conditions.
The main materials of steel wire screw sleeve are divided into three kinds: stainless steel, copper alloy and high temperature alloy.
First, the tensile strength of stainless steel at room temperature is >1400 Mpa, its stable working temperature is 425 DEG C short time, 315 DEG C for a long time. The use of thread can enhance the friction, water liquid chlorine corrosion resistance of lightweight structures under normal circumstances. Stainless steel is currently the most commonly used steel wire screw sleeve material, mainly for 304, 316, 321 materials.
304 - 18/8 GB grade stainless steel, 0Cr18Ni9 stainless steel is one kind of universal material, widely used in the production of good overall performance requirements (corrosion resistance and molding equipment and parts). 304H is 304 heat resistant steel meaning, carbon content 0.04~0.1, Ni:8~11, other nominal content and the same as 304. 304H has good corrosion resistance, high lasting strength and organizational stability, cold deformation ability is very good, the maximum temperature can reach 650 DEG C, oxidation temperature up to 850 degrees C.
316 - GB grade 0Cr17Ni12Mo2, 304 after second steel is widely used, mainly for the food industry and surgical instruments, add the Mo element to obtain a special structure of corrosion in seawater, and other kinds of media, than the 304 because it has antioxidant corrosion ability better, thus "marine steel" to use.
321 - GB brand 1Cr18Ni9Ti, add Ti element, improve the material resistance intergranular corrosion, its strength, wear resistance, corrosion resistance is better than 304, uniform stress, long service life.
Two, the room temperature tensile strength of copper alloy is >1000 Mpa, its stable working temperature is 300 DEG C short time, long time of 250 DEG C. The utility model is mainly used for conducting or self lubrication, and requires the condition of copper and the screw connection which is often regulated to rotate.
Three, high-temperature alloy room temperature tensile strength is >1400 Mpa, its stable working temperature is 750 DEG C short time, 550 C long time. This material threaded sheath is mainly used in aerospace technology equipment, aircraft, engines, internal combustion engines, turbine compressors. The company currently uses high-temperature alloy wire mainly:
Inconelx-750 - for the American brand, Japanese brands of NCF750, corresponding to GH4145 of our country, the alloy has good corrosion resistance and oxidation resistance at 980 DEG, 800 DEG C with higher intensity, 540 DEG C has good performance with relaxation, but also has good formability and weldability, have excellent mechanical properties in the environment of low temperature, the alloy is mainly Y[Ni3 (Al, Ti, Nb)] of nickel based high temperature alloy aging strengthening.
The United States Nimonic90, grade UNSNo7090, corresponding to our GH90, the alloy is aging hardening nickel cobalt base superalloy, cobalt and a higher amount of reinforcing elements, the alloy has high tensile strength and creep resistance at 815~870 DEG C, good oxidation resistance and corrosion resistance, fatigue strength in the hot and cold alternately high effect and good formability and weldability.
Difference between 302 and 304:
The 304 is a universal stainless steel, 302 stainless steel is essentially with a higher carbon content of 304 stainless steel varieties, cold can make it through to obtain high strength, in general, 302 more than 304 poor corrosion resistance, strength is 304 higher, the price is 304 cheaper.
So for how to buy threaded sheath friends, understand the thread sheath material is very important, so as to choose the right product.