Major breakthroughs have been achieved in the domestic substitution of high-end mold steels, with the PXZ steel grade making its domestic debut.
Release time:
2025-11-26
In October 2025, a major breakthrough was announced in China’s R&D and production of high-end mold steels: the PXZ high-end plastic-alloy mold steel—designed to meet internationally advanced standards—has successfully entered mass production and delivery. This milestone marks the end of the long-standing monopoly held by foreign brands in China’s high-end mold-steel sector and represents a significant achievement in the domestic substitution of critical materials.
The newly launched PXZ mold steel is a pre-hardened plastic alloy tool steel that, thanks to its core advantages of high strength, high hardness, and exceptional wear resistance, is widely suited to the manufacturing needs of precision injection molds in industries such as automotive, home appliances, and electronics. Its performance metrics are fully aligned with the standards for leading international grades of specialty steels. This grade places extremely stringent technical requirements on product purity, compositional homogeneity, and hardness control. Compared with the conventional mold steel 2311, PXZ’s hardness control range has been precisely narrowed to an exceptionally tight band of 30–33 HRC, reducing the allowable variation by nearly half. Industry experts aptly describe this as “walking on a tightrope”: if the hardness is too high, downstream machining becomes significantly more challenging, potentially even resulting in the material being “unable to be cut”; conversely, if the hardness is too low, the steel cannot meet the long-term service-life requirements of precision molds, placing extreme demands on the precision of every step in the entire production process.
The greater technical challenge stems from the requirement to double the alloy content. In the PXZ steel grade, the molybdenum content ranges from 0.2% to 1.0%, more than twice that of conventional mold steels. As a key alloying element for enhancing steel performance, molybdenum significantly improves wear resistance and structural stability; however, during continuous casting, high molybdenum levels readily give rise to critical defects such as transverse and longitudinal cracks in the billets, leading directly to product scrap. This technical hurdle has long constrained the R&D progress of high-end domestic mold steels. To overcome this industry pain point, a domestic technical task force established a dedicated R&D team that launched a “precision assault” across the entire process—from steelmaking and continuous casting to heat treatment—systematically breaking through technical bottlenecks.
In the core processes of steelmaking and continuous casting, the technical team conducted hundreds of trials to optimize critical process parameters, employing a “needlework-like” level of precision in dynamically controlling casting speed, cooling-water flow, and protective pouring practices. This approach successfully mitigated the common crack defects in the continuous casting of high-alloy steels, thereby ensuring consistent billet quality. Upon entering the heat-treatment stage, the team undertook multiple rounds of process iteration and data analysis, tightly constraining furnace-temperature fluctuations to an ultra-narrow range of ±3°C. Ultimately, they finalized the optimal heat-treatment parameter set, achieving precise hardness matching for every finished steel plate. The project commenced trial production in August 2025 and completed delivery of all batches by early September. Both the overall product qualification rate and the performance-match rate reached industry-leading levels, earning high recognition from downstream application companies.
The successful domestic production of PXZ mold steel not only enriches China’s portfolio of high-end mold steels but also fundamentally reduces the reliance of domestic mold manufacturers on imported materials. Previously, such high-end mold steels were entirely sourced from countries like Germany and Japan, resulting in high procurement costs, lengthy lead times of 3 to 6 months, and significant supply-chain instability due to global supply-chain disruptions and tariff adjustments. The mass production of PXZ steel will cut related mold-manufacturing costs by 15% to 20%, substantially shorten delivery cycles, and provide robust material support for the high-quality development of downstream industries such as automotive, electronics, and home appliances. At the same time, it enhances China’s influence in the international market for high-end specialty steels and accelerates the transformation of China’s mold-steel industry toward greater sophistication and self-reliance.
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