Boss consulting, stainless steel type mold steel, used in injection molds, to make needle valve hot runner sealing, is a round part, the service life is millions of times, what good materials are recommended?
Now I use S136, the effect is not ideal, the front end of the needle valve does not take long, it is deformed, I want to be more durable. [Yuhui Mould Steel Huang Zipeng's Diary No. 784]
Stainless steel is not really not rusty, it is the abbreviation of stainless acid-resistant steel, which is used in specific weak corrosive environments such as air, steam, and water, and is not easy to rust, which is called stainless steel.
Stainless steel is often divided into martensitic steel, ferritic steel, austenitic steel, austenitic-ferritic (duplex) stainless steel and precipitation hardening stainless steel according to the microstructure.
In our mold industry, martensitic stainless steel is used more. Martensitic steel has good processing performance when it is not quenched, has high hardness after heat treatment, good wear resistance, and low cost compared to other steel grades.
Stainless steel with good smelting quality can be done with high mirror polishing, and the durability is very high for high-demand plastic molds.
S136 is a kind of 4Cr13 martensitic stainless steel, the alloy composition is usually 13% chromium, about 0.4% carbon, and the hardness is HRC45-50 after heat treatment.
At present, the needle valve has encountered the problem of deformation after a period of use, mainly because the strength of the steel is not enough, and it is succumbed and deformed during use. When injecting some rubber materials with high glass fiber content, it is easy to encounter this problem, and the gate is easy to expand.
Coupled with the fact that the boss's target life is 1 million times, you can choose stainless steel with higher hardness.
The more common is 440C, 9Cr18Mo, which is a martensitic stainless steel with a carbon content of about 1%, and the carbon content is more than 2 times that of S136.
The boss also asked me, can FS139 be used? I checked it on the Internet, this is a chromium content of 16%, carbon content of 0.4%, and then add other trace elements, it is said that the hardness after heat treatment also has HRC54-58.
FS139 is close to 4Cr16Mo1 type stainless steel. According to past experience, the main feature of 16% chromium stainless steel is that the rust resistance and durability are better than ordinary S136, and the hardness of use generally does not exceed HRC55, and his wear resistance is definitely not as good as 440C high-carbon steel.
If you want to try to compare the effects, you can also do it.
I am Huang Zipeng, from Liaobu, Dongguan. Yuhui die steel, 3 of the world's top 500 are in use, Kyocera has purchased for 7 consecutive years.
If the boss in front of the screen also has a similar injection mold needle valve hot runner sealing port with S136 quickly deformed working conditions, you can also come to Yuhui mold steel Huang Zipeng to try it.