Effect of Normalizing Annealing Temperature on Precipitates and Texture of Nb-Cr-Bearing Decarburized Grain-Oriented Silicon Steels

The evolution of precipitates and texture was investigated in Nb-Cr-bearing decarburized specimens after normalizing at different temperatures. Enough inhibitors, including Nb(C,N), were obtained, of 20~40 nm in size. Increasing normalizing annealing temperature leads to the number density of the precipitates decreasing and that of mean size increasing. The Goss texture content in the decarburized specimens decreases in different degrees compared with the normalized ones. The minimum Goss texture and maximum ∑9 grain boundaries were obtained in the decarburized specimen normalizing at 950 °C and in this specimen, enough fine dispersed inhibitors, weak but relative stable Goss texture and uniform grain size will be beneficial for Goss grains growth in secondary recrystallization, according to the coincidence site lattice theory.

Evaluation of eddy current signatures for predicting different heat treatment effects in chromium–vanadium (CrV) spring steel

The nondestructive test method (eddy current) was employed to study the effect of different heat treatment cycles (normalizing, annealing, quenching, and tempering) on chromium–vanadium (CrV) spring steel. The calibration of eddy current setup was carried out as per ASTM E566 and frequency optimization for the evaluation of heat treatment was carried out in absolute mode using shielded eddy current testing core probe. The eddy current signatures successfully distinguished the effect of different heat treatments cycles and variation in hardness for CrV samples. Scanning electron microscopy images confirmed the different microstructures as predicted by the eddy current testing.

Normalizing, Annealing, and Spheroidizing Treatments; Ferrite/Pearlite and Spherical Carbides

This chapter describes heat treatments that produce uniform grain structures, reduce residual stresses, and improve ductility and machinability. It also discusses spheroidizing treatments that improve strength and toughness by promoting dispersions of spherical carbides in a ferrite matrix. The chapter concludes with a brief discussion on the mechanical properties of ferrite/pearlite microstructures in medium-carbon steels.

Effect of Coiling and Normalizing Annealing on the Microstructure of a Newly Developed Cold-Rolled Non-Oriented Electrical Steel

In order to improve the magnetic properties, copper was added to cold-rolled non-oriented electrical steel with low carbon and low silicon. The grain sizes and precipitates in hot-rolled bands of the investigated steel were quantitatively studied. The results show that the recrystallization of deformed grains has been completed in the coiled bands and the recrystallized grains are fine due to low coiling temperature and pinning effect of precipitates. But grains grew up obviously after normalizing annealing at 850°C for 1h because the mobility of grain boundary is so good at elevated temperature that pinning effect of precipitates can’t prevent the migration of grain boundary. Thus, normalizing annealing is necessary to obtain large grains in hot-rolled band. In addition, the typical morphologies of precipitates in hot-rolled bands are square, rectangular, hexagonal and triangular and they are identified as AlN phase based on EDS and SEAD analysis, which can form by epitaxial growth mode. For the hot-rolled bands coiled at 550°C, the increase of average size and volume fraction of AlN particles with coiling time is mainly related to the growth of AlN particles, whereas for the hot-rolled bands coiled at 650°C, the decrease of average size and the increase of volume fraction of AlN particles with coiling time are chiefly attributed to the precipitation of many small AlN particles. The volume fraction of AlN particles increases with coiling temperature because they precipitate more quickly at 650°C than at 550°C.

Effects of Normalizing Annealing on the Recrystallization Texture of 4.2wt.%Si Non-Oriented Electrical Steel Thin Sheets

The 4.2wt.%Si non-oriented electrical steel thin sheets with the thickness of 0.30mm were produced by the conventional procedure including hot rolling, cold rolling and annealing. The recrystallization texture was analyzed with emphasis on the effect of normalizing annealing. The results show that the  fiber with peak at {111} is weaker and η fiber is stronger in the sheets with normalizing annealing than those without normalizing annealing, either under the cold rolled reduction of 77% or 86%. Effects of normalizing annealing on the recrystallization texture can be explained in terms of the characteristic of the shear bands formed during cold rolling process.

The Physical Simulation of the Normalizing Rolling of the Steel Plate in Strength Category 350÷460MPa

The article presents the results of physical simulations of the process of rolling plates of steel in the strength category 350÷460MPa on the finishing stand of a reversing mill. The simulations were performed for three steel grades and final plate thicknesses 40mm. The purpose of the simulations was to select the conditions of plate deformation to obtain, directly after rolling, structure of material corresponding to the structure obtained from normalizing annealing. Thus, the simulations reflected the normalizing rolling process. The research carried out has allowed to elaborate the new technology of production of rolling plate without an additional thermal treatment like normalization. It allow to decrease a time and total cost of production for this sort of product.