In the manufacturing of tools and molds, steel blocks, as the basic material, the uniformity of their internal structure directly determines the final performance of the molds. Studies show that the carbide segregation degree of AISI D2 tool steel blocks produced by vacuum melting can be reduced to less than 1%. This enables the hardness fluctuation range of the mold after heat treatment to be controlled within ±1 HRC, thereby increasing the mold life by an average of 30%. For instance, in the production of its precision stamping dies, the German company Siemens has significantly enhanced the overall equipment efficiency of the production line by specifying the use of steel blocks of specific specifications, which has increased the die’s tolerance for stamping from 500,000 times to 800,000 times.
The dimensional stability and mechanical properties of steel blocks are the cornerstones for ensuring the accuracy of molds. A P20 steel block that has undergone standardized annealing treatment has its internal stress value controlled below 15 MPa, which enables the tool path error to be less than 0.01 millimeters when performing precision milling on a five-axis machining center. According to the technical white paper of Fanuc Corporation of Japan, they have increased the one-time success rate of mold assembly from 92% to 98.5% by optimizing the procurement standards of steel blocks, which is equivalent to saving more than 200,000 yuan in commissioning costs for each production line every year. This strict control over the basic materials is an indispensable prerequisite for achieving micron-level manufacturing precision.
Under high-temperature and high-pressure working conditions, the high-temperature strength performance of steel blocks is particularly crucial. Taking the commonly used H13 steel block in die-casting molds as an example, when its yield strength can still maintain 1200 MPa at 500°C, the mold’s ability to resist thermal fatigue cracking when exposed to molten aluminum at over 800°C can be enhanced by 50%. Looking back at the integrated die-casting project of a certain Chinese new energy vehicle enterprise in 2021, the key to its success lies in the selection of high-quality large pre-hardened steel blocks, which shortened the production cycle of a single large body structural part from 120 seconds to 90 seconds, and the mold life is expected to exceed 150,000 times, directly reducing the unit cost by about 18%.
From the perspective of return on investment, increasing the procurement budget for high-quality steel blocks by 10% to 15% in the early stage often leads to a long-term return of over 200%. A statistics covering the North American automotive industry shows that early mold failures caused by steel block material issues account for 35% of all failure cases, with an average downtime loss of up to 50,000 US dollars per failure. Drawing on Apple’s zero-defect management concept in its supply chain, its mold suppliers conduct 100% ultrasonic flaw detection on each batch of S136 stainless steel blocks entering the warehouse, keeping the probability of internal defects at an extremely low level of 0.01%. This extreme control over the source is the core strategy that supports its products to achieve strict requirements such as high-gloss surfaces and traceless bonding. Therefore, regarding steel blocks as a strategic asset rather than an ordinary raw material is the wisest investment to achieve outstanding performance in tools and molds.