Processing Strategies for Hot-Rolled Medium-Mn Steels

The study aims at reviewing manufacturing schedules for hot-rolled and intercritically-annealed and thermomechanically processed medium-Mn sheet steels. Major differences between these two types of processing are indicated. They include initial microstructure (low-C martensite for hot-rolled products and deformed austenite for thermomechanically processed products), partitioning of alloying elements (depending on intercritical annealing or batch annealing conditions) and microstructure prior to cooling (ultrafine-grained lath mixture of ferrite and austenite for hot-rolled, intercritically annealed products and deformed austenite for directly cooled products). The comparison of typical microstructures (LM, SEM) and phase transformation behavior are presented. A role of Mn as an austenite stabilizer in a range used for medium-Mn steels is explained. Some results are provided for economic steels containing 3% and 5% Mn.

Failure Analysis of Coil Racks in a Batch Annealing Furnace Using Finite Element Methods

In this work, a series of finite element method simulations were performed on cooling racks used for the loading and unloading of steel coils in a batch annealing furnace. Normal furnace operations were simulated using ANSYS Thermal FEA and ANSYS Mechanical FEA to reproduce the thermal and structural loads experienced by the racks, as well as additional lifting forces representing removal by forklift after annealing. In addition to warping found due to uneven heating from the radiative elements of the furnace, severe stress leading to failure was identified on the base of the racks from the lifting force. These results correspond with failures seen in the actual units. The simulation data was used for design adjustments to reduce the damage from the above sources.

EFFECT OF ANNEALING CYCLES ON DEEP DRAWABILITY OF LOW CARBON TITANIUM ADDED STEEL

EFFECT OF ANNEALING CYCLES ON DEEP DRAWABILITY OF LOW CARBON TITANIUM ADDED STEEL. Maximum mechanical properties and deep drawability of low carbon titanium added steels was obtained after heat treatment with simulation batch annealing cycles in an industrial process. The effect of holding times and holding temperatures on deep drawability were studied using tensile test for measuring normal anisotropy (r-value) and strain hardening exponent (n-value). Scanning electron microscope were employed for observation of microstructure in steel sheets. X-ray diffraction with pole figure techniques were also used for measuring texture of annealing. Results showed that as the temperature was increased up to 900 oC, both r and n values increased gradually and peaked in the temperature of 850 oC. This results showed that formability of sheet materials increased until batch annealing temperature reach 850 oC as increasing the ratio of intensities {111} /{100}. The largest mean r value of almost 2.6 was obtained in slow heating at holding temperature of 850 oC with n value of 0.27.

Factors Affecting the Mechanical Properties Variation after Annealing Of Cold Rolled Steel Sheet

Cold rolled steel industry in type of batch annealing furnace, the mechanical properties of steel sheet have variation by each position. The parameters of annealing temperature and time were analysed to work out the source of mechanical properties variation. This experiment is using low-carbon steel sheet that were cold rolled at the same reduction ratio. Then annealed applying by different annealing temperature and soaking time in laboratory furnace. The mechanical properties which were examined. Yield strength, Tensile strength, %Elongation and Hardness. The result showed that (1) Increasing the annealing temperature could remarkably decrease the yield strength, tensile strength and hardness, whereas the %Elongation could be increased. (2) Increasing the soaking time could slightly effect on mechanical properties. (3) The annealing temperature of 650°C with soaking time of 2 hr should be applied to provide the mechanical properties close to target value (4) Grain size of the workpieces trended to be grown from the annealing temperature of 610°C.The experiment it can be concluded that annealing temperature and soaking time have significant effect on the mechanical properties variation in batch annealing.