Upsetting test of metal materials
In the production of large quantities of metal materials in the past and in the future, the use of molds to forge (press) semi-finished or finished parts is one of the main directions of
the machinery manufacturing industry. It is crucial to measure the quality of the steel by the upsetting test of the imported steel. The problem.
Applying pressure to the metal material along the axial direction of the sample at room temperature or in a hot state to compress the sample, and verifying the ability of the metal to
undergo plastic deformation of the upset forging at a specified forging ratio, such as 1/3 or 1/2 of the original length and displaying Metal surface defects must be subjected to upsetting
operations such as riveting and boring.
The results of statistical analysis of hot upset forging found that the rolling defects in the production process of scratches, folds and surface microcracks are the direct cause of hot upset cracking.
Surface crack, during the rolling process, due to the large amount of rolling deformation or uneven wear of the hole type, the wrinkle defect caused by uneven deformation of the blank in the hole type is caused.
Measures to reduce surface cracks:
(1) Check each hole type after rolling a certain amount to optimize the water cooling system to reduce roll wear
(2) Reduce the temperature difference at the watermark to ensure that the temperature of each steel is within the standard range.
(3) It is required to install two water pipes for the round steel rolling export guide to purify the rolled parts to ensure that the scale is cleaned and the surface finish of the finished product is improved.
(4) Optimize the installation of the cooling water pipe of the rolling mill and standardize the roll surface temperature of the roll (≤50 °C).
(5) When stopping rolling for various reasons, the cooling water must be closed after 10 minutes of stop rolling to ensure sufficient cooling of the roll hole.
(6) Improve the roughing pass type hole system of No. 1, 2, and 3, improve the processing stress state, and solve the surface crack of round steel
(7) rough-rolling trial laser roller, and tracking the surface quality of the roller, rationally quantifying the rolling tonnage of the laser roller, and simultaneously researching the horizontal stripes, and
improving the surface quality of the roller by grinding;
(8) Improve the material of the roll. The rough rolling is gradually changed from the semi-steel roll to the pearlite roll. The original rolling is gradually changed from the original pearl roll to the bainite
roll to improve the surface quality of the roll and implement the whole process quality control.
(9) Improve descaling equipment, optimize air duct auxiliary, reduce the influence of iron oxide scale on cracks
The above 9 points reduce the surface cracking from the aspects of process, equipment, management, etc. to improve the hot upsetting performance of the metal material and improve the metal process performance.