Beam Blanks Research Articles

The effect of casting conditions on the formation of longitudinal surface crack in the beam blank caster

To understand the effects of casting conditions on the formation of longitudinal surface crack, the crack morphology of over 2000 charges at scarfed beam blanks were investigated. The results whow that the most sensitive crack susceptibility range of carbon contents lie in the 0.12–0.13 wt.% range. This was due to the effect of shell irregularity between mold surface and solidified shell withdrawn by δ-γ transformation and the embrittlement phenomena by liquid film of soluble elements such as phosphorous and sulfur at the dendrite interface. It was found that the increase of crack formation is attributed to the increase of phosphorous and sulfur contents segregated at the dendrite interface. The increase of crack formation with increasing Phosphorous and Sulfur contents is due to the enlargement of the ΔT range, which is defined as the temperature difference between LIT (liquid impenetrable temperature) and ZDT (zero ductility temperature). The effect of casting speed on crack formation shows a linear relationship. As casting speed is increased, the solidified shell had little time to grow and the width of shell became smaller. As, the heat flux from the thinner shell increased, the thermal strain was increased, increasing crack formation.

« Turn key » steelplant for Stahlwerk Thuringen (ARBED Group) erected by VAI within 16 months

In an extremely short time, a new steel plant was designed and built for the supply of beam blanks to the section mill of Stahlwerk Thuringen. Modern technologies are used, in particular for the DC electric arc furnace, and a high degree of automation has been achieved from the scrap yard to the shipment of the finished product. Thanks to a precise coordination of the steelmaking and the rolling mill operation, the rate of hot charging has been maximized.

An expert system for process planning in breakdown rolling of H-beams

An expert system for inferring the processes in breakdown rolling of H-beams is proposed. In breakdown rolling, H-beams with various dimensions to be supplied to a subsequent universal rolling process are manufactured by using grooved rolls from beam blanks with a single geometry. A database is constructed with the knowledge acquired from the results of rigid-plastic finite element simulations of breakdown rolling by using simplified three-dimensional elements undergoing generalized plane-strain deformation. In the database, the geometries of the beams before and after rolling are stored for various geometries of roll grooves. Processes in breakdown rolling are generated by tracing the forming paths backwards from the final beam geometry until reaching the initial beam blank geometry. In the process generation, the FEM database is searched to find similar geometries to the beam under consideration on the basis of the statistical method. The workability for the inferred process is verified by the finite element simulation in the last stage of the expert system.

Forging of heavy beam blanks

A new technique for the production of heavy sections has been studied, where the conventional roughing stand is replaced by a forging press. The main result of this replacement is — amongst other things — decreased building area, decreased need for reheating capacity and the possibility of producing heavier beams from continuously-cast blooms. The new method is in some respects comparable with high-reduction processes such as the GFM and the Kocks and Sacks continuous-forging machines. The beam blank, i.e. the semi-product of the roughing stand, is produced by the simultaneous action of four dies; two opposed vertically-working and two opposed horizontally-working. The pair of vertically-operating dies forms the web of the beam blank. The1dies are designed to control the material flow and give a controlled spread and elongation. The main part of the material that is forced aside by the web reduction therefore spreads in a direction transverse to the feeding direction: this material is worked by the horizontally-acting dies to form the flanges of the beam blank. This paper deals mainly with the force requirement, die shape and production capacity of the process, but a simple economic comparison between the forging and rolling techniques is also made.

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