The characteristics of high-end castings are high level of performance and high stability of quality, both of which are indispensable. Some domestic enterprises often attach great importance to the research and development, the level of trial products is high, but once put into production, it is slack and the quality fluctuates unsteadily. The author believes that high-end castings must have two characteristics: one is the requirements of high quality and high performance; the other is the high stability of casting quality in production.
1. Low temperatureaxle box
The market demand of low-temperature ductile iron is put forward due to the application requirements in cold areas. The quality requirements of the low-temperature ductile iron rail castings produced by Changzhou Huade company are: tensile strength > 400 MPa, yield strength > 240 MPa, elongation > 18%, and the low-temperature impact absorption energy is greater than 12j at – 20 ℃, – 40 ℃ and – 50 ℃, And “zero tolerance” shall be applied to the track parts that affect the safety hidden danger or failure of high-speed train. From the above data, it can be seen that high quality is reflected in ensuring the safe driving and personal safety of high-speed trains; high performance is reflected in reaching the tensile strength of 400 MPa and elongation of more than 18%; at the same time, the impact absorption energy at – 20 ℃, – 40 ℃ and – 50 ℃ is above 12 J; high level is reflected in 18742 sets of bogie axle boxes produced by 4000 heats, and there is no one unqualified product.
It is very important to innovate independently and form their own intellectual property rights in the production of high-end castings. Changzhou Huade company has applied for the patent of manufacturing crh380 Bogie Axle Box with qt400-18al (- 40 ℃), but they did not stop there. They also studied qt400-18al at – 60 ℃ and got good results.
2. Low temperature ductile wind power ductile iron castings
The high quality and high performance of the large section low temperature ductile wind power nodular iron castings produced by ZHY casting are fully reflected in the performance of the large section casting body sleeve sample. The impact absorption energy of the 2.3 MW wheel hub castings is 12 J at the thickness of 200 mm, the hardness of 138 HBW and the impact absorption energy of – 20 ℃; the 4.5 MW wheel hub castings are sampled at the thickness of 190 mm, the tensile strength of 368 MPa and the yield strength of 241 MPa, The impact absorption energy is 14.9 J; the 4 MW main shaft is sampled at the thickness of 120 mm, the tensile strength is 353 MPa, the yield strength is 243 MPa, and the impact absorption energy at – 20 ℃ is 11 J