H13 Injection Mold Vacuum Heat Treatment

---

Overview
H13 injection mold steel has high toughness cold and hot fatigue resistance, which can greatly improve the service life of hot mold.At the same time, it can also be used for other shaft types and components that require high strength and hardness, so it is welcomed by the majority of users.

H13 steel has high thermal strength, heat resistance and hardenability due to its large amount of Cr, V and other alloying elements.According to literature, martensite tissue can be obtained by air cooling for test rods ≤0300mm.In order to facilitate mechanical processing and improve its service life, the heat treatment technological parameters of the steel were studied.

H13 Injection mold heat treatment process
Shanghai Gehang Vacuum Technology Co., Ltd. carried out 880℃ heating in VOGQ-446-2 two-chamber vacuum oil quenching furnace with the material hardness of HB416.After cooling at ≤30℃/h, the hardness of the material is HB225.The hardness of the material was HB221 after heating at 860℃ and cooling at ≤20℃/h.850℃ heating,≤20℃/h cooling.The hardness of the obtained material was HB208.

From the above test results, it can be seen that the heating temperature of H13 steel spheroidizing annealing should be within the two-phase area of austenite plus undissolved carbide, i.e., 850~ 860℃.At this temperature, the content of carbon and alloying elements in austenite is less, and the stability of supercooled austenite is poor, which is conducive to spheroidization.At the same time, undissolved carbides are retained and cooled at a slower cooling rate during cooling. The supercooled austenite transformation can only take these undissolved carbides as the core to form granular carbides, thus speeding up the spheroidization process.The slower the cooling rate, the larger the carbide particles and the lower the hardness of the steel.Therefore, by controlling the heating temperature and cooling rate of spheroidizing annealing, the ideal machining hardness can be obtained.

The quenching process test was carried out in the region of 960~ 1180℃, and oil cooling and air cooling were used.The main test results were as follows: heating at 1020 ° C, air cooling and oil cooling respectively, and the hardness of the obtained material was HRC52~55.The soil was heated at 10℃ and cooled by air and oil respectively. The hardness of the obtained material was HRC55~58.It can be seen that the same hardness can be obtained by air heating and oil cooling of the steel, which belongs to martensitic type of steel.
Hardness and tempering temperature curves of H13 steel after heating oil quenching with 1050 soil at 10℃ and tempering twice at different temperatures.

H13 steel quenched at 1050℃ has a secondary hardening phenomenon, and its temperature is between 500~530℃. With the increase of tempering temperature, the tempering hardness above 520℃ is above 55HRC.

Conclusion
(1)H13 steel is heated at 850~ 860℃ and cooled at a cool speed of <30℃/h, and can be fuzzed to the ideal processing hardness (HB208-225;The same).To speed up the cooling speed high hardness, add エ against cutting.

(2) the H13 steel at 1050 ℃ quenching heating temperature カ inches, can completely protect nitrate alloy elements into fully, and then the air cooling can take more than a HRC58 eight hardness, air-cooled markov shape steel.

(3) the H13 steel in 500 ~ 530 ℃ tempering with secondary hardening phenomenon, 520 ~ 540 ℃ tempering hardness can be twice 込 HRC50 ~ 55.The top end of the quenching oil is more varied in circumference due to the variations in the variations of the coolant speed and the variations in > variations (compared with the variations in the latter end of the quenching oil).

In conclusion, the variations in the shape of the parts, the variations in the heat treatment and the material, especially the Ms spot, are highly influential.

Editor: Frank Lee
Copyright: SIMUWU vacuum furnace