Archive for the Rebuilds Category

Hot Strip Mill Work Roll and Back Up Roll Chock Bearing Design Improvements and Value Add Features
Glunt Industries was able to significantly lower the customer’s maintenance spend and improve production uptime by adopting a Total Cost of Ownership philosophy to regularly maintain the assets, identify innovative means to redesign chock components and introduce new materials/coatings to extend component life.

Regular maintenance included thorough inspection and maintenance of bearings, seals, wear plates, hydraulic roll balance systems for all components. The program has resulted in a reduction of downtime by 1200 minutes or 52% from previous supplier resulting in a $3,600,000 productivity gain for customer on an annualized basis

In addition to the regular maintenance program, Glunt engineered a one-piece carrier ring solution for the Hot Strip Millwork roll chocks. This eliminated the two-piece carrier adjusting nut and reduces injury chance during de-chocking operation. Additionally, this will reduce roll shop labor time by 10 min/chock during de-chocking and re-chocking procedure.
Glunt was able to design a new umbrella-style wiper seal design and material that will eliminate scale buildup around roll balance piston and packings eliminating premature wear to the packing and pistons and dramatically reducing downtime

This change after full implementation will result in longer piston life resulting in annualized cost savings of $120,000 annually.

Glunt also introduced a new roll balance piston coating process and material that was designed to offer a longer piston life via the carbide coating. Previously the roll balance piston surface was non-coated chrome surface. The new coating system will aid to eliminate downtime due to worn and/or leaking packings resulting in potential annualized cost savings of $150,000.

Due to these program initiatives and design upgrades, the customer has seen a dramatic reduction in the number of seized roll/bearings on chocks as well as the documented lower costs and improved production time.

Glunt Industries was able to use its expertise in design and innovation by optimizing the OEM design and material optimization to rebuild a Hot Strip Coiling Mandrel that is expected to run 1.5 million tons and extends run campaign life to over 5 million tons before servicing.

From a material selection perspective, Glunt substituted proprietary stainless steel that had higher performing mechanical properties (Y, T, %elong) versus the OEM chosen 4140 material to guarantee prolonged performance with the pins and links. The components were then machined and processed further through nitriding to create a superior, case hardened surface.
Additionally, Glunt optimized the segment components by substituting the as-cast 304 stainless with forged 8620, case hardened steel alloy to improve strength and toughness properties. The segment components were then weld overlaid with a proprietary stainless mill clad to further improve performance and wear.

From a design optimization standpoint, Glunt was able to improve on the OEM construction by adjusting and tightening all internal component fits and clearances to provide superior performance for the mandrel campaign. These upfront design changes were done in concert with the customer and resulted in Hot Strip Coiling Super-Coiler Mandrel that met and significantly exceeded this major Mini-Mill customer’s needs/ expectations.