The influence of the contact point of wire rod on the inhomogeneity of cooling behavior within wire ring was investigated to reveal the fundamental cooling mechanism of wire rod during the Stelmor cooling process. A hotspot, a relatively high-temperature region within wire ring compared with other regions, was generated in both the central (WRc) and edge (WRe) regions of the wire ring. The WRe exhibited hotspots regardless of ring configuration. Meanwhile, the WRc exhibited hotspots with an inline arrangement; otherwise, no hotspot occurred in the WRc with a staggered arrangement. Compared with the middle regions of the wire ring, hotspots easily occurred at both the WRc and WRe due to the low-contact angle of the two wire rings. Moreover, the possibility of hotspot formation increased with increasing wire diameter due to the high-contact area and load caused by the weight of the wire rod. This is the primary reason why the WRc with a large diameter had hotspots despite the large ring pitch. Three solutions were suggested to improve the homogeneity in the mechanical properties within wire ring.
Keywords: Stelmor; contact point; hotspot; steel wire rod; uniform cooling.