Successfully Delivered 6,000 Tons Of 80mm Extra-thick Stainless Steel Plates

Recently, GNEE Stainless Steel successfully overcame the challenge of controlling the mechanical properties of ultra-thick stainless steel plates, completing the delivery of over 6,000 tons of plates ≥80mm thick for a major international energy project. The plates included individual pieces up to 150mm thick and single plate weights of up to 28 tons, setting a new global record for delivery volume in this product category.

 

 

In the global high-end equipment manufacturing sector, the performance and cost of ultra-thick stainless steel plates have long been bottlenecks limiting industry advancement. Traditionally, the production of plates ≥80mm in thickness has been constrained by the reduction ratio requirements. To meet mechanical property standards, the rolling reduction ratio of continuously cast slabs must exceed 3:1. However, standard slab thickness is typically limited to 200–220mm, which restricts the final rolled plate thickness to under 70mm.

To produce thicker plates, manufacturers must rely on ingot casting, forging, and hot rolling, a route with long lead times and low yield rates. Moreover, large ingots often suffer from metallurgical defects such as shrinkage cavities and large inclusions, making it difficult for the finished plates to meet strict ultrasonic testing (UT) standards.

 

GNEE's technical team took an innovative approach, independently developing a breakthrough process that overcomes key challenges in ultra-thick plate production-including thick-slab casting, differential-temperature heating, controlled rolling and cooling, online solution treatment, and shape control. As a result, the plates exceeded customer expectations in all key metrics, including full-thickness tensile strength, -196°C Charpy impact toughness, grain size, and inclusion cleanliness. The plates achieved zero defects in high-standard UT inspection, marking a major leap from "follower" to "leader" in China's stainless steel thick plate manufacturing capability and significantly enhancing the global competitiveness of Chinese ultra-thick stainless steel.

 

Thanks to the universality of this new process, GNEE Stainless Steel has extended the technology to a full range of high-end stainless steels. In addition to standard grades such as 304, 321, and 316, ultra-thick duplex stainless steels including S32750, S32205, and S32304 have also been delivered in bulk, with thicknesses up to 150mm, fully meeting ASTM standards.