Speaker
Description
The supply of large-diameter bars in stainless and special steels has historically been constrained by process limitations, with forging routes dominating production above 6 inches due to perceived advantages in internal soundness and metallurgical control. However, increasing demand for consistency, productivity, and cost efficiency in critical applications is progressively redefining the processing landscape.
This work presents the commissioning of a new SBQ rolling mill at FRISA, enabling the production of round and square bars from 3.75 up to 16 inches in diameter, supported by integrated straightening, peeling, ultrasonic inspection (UT), and heat treatment facilities. This installation represents a significant expansion in the processing capability of large-section materials, traditionally considered unsuitable for rolling in high-integrity applications.
Particular emphasis is placed on precipitation hardening stainless steels such as 17-4PH, where large cross-sections have historically exhibited challenges related to segregation, microstructural variability, and inconsistent response to heat treatment. In addition, results are presented for austenitic grades (304, 316), hot work tool steel H13, and high-cleanliness steels for bearing applications, demonstrating the robustness of the process across multiple alloy systems.
Through the application of high total reductions (typically well above 4:1), controlled thermomechanical processing, and optimized heat treatment cycles, the developed route achieves enhanced microstructural homogeneity and property consistency. Industrial data show low mechanical property variations across the section, full compliance with ultrasonic quality requirements, and improved surface integrity after peeling.
The results indicate that modern SBQ rolling, when properly engineered, can deliver quality levels competitive with forging routes while offering increased productivity and process stability, particularly in applications where consistency and repeatability are critical.
This work positions large-diameter rolling not only as a complementary solution to traditional routes, but as a technically robust and industrially scalable alternative for selected high-performance applications, opening new opportunities in the supply of stainless and special bar products.
| Speaker Company/University | FRISA Steel |
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