Effect of process parameters on performance of grooved hot rolling of SAE 4340 steel bars

Abstract

ABSTRACT SAE 4340 alloy steel is used in structural parts, forging industry, gears and shafts used for power transmission and landing gears of aircraft. Basic production process of the metal bar involves heating the billet in reheating furnace up to 1200°C–1210°C followed by passing it through a pair of grooved rolls in a rolling mill. The roll separating force, driving torque and end crop length are the important issues to be controlled for quality production, maximization of yield, minimization of rolled bar process scrap, safety of mill and reduction in energy consumption. These response parameters depend on several process parameters – rolling speed, billet temperature, reduction ratio (strain), billet size (cross-section area), roll diameter, etc. This paper presents a study on the effect of process parameters on these response parameters during grooved rolling of SAE 4340 steel. Simulation of the rolling process has been attempted using FORGE® Nxt 1.1. The simulated results so obtained have been validated through experimental results obtained in a rolling mill, following statistical tests. Regression models showing relationship between the process parameters and the response parameters have been developed. Significant model-terms have been obtained using analysis of variance.