Effect of Reaction Temperature on Pickling of 430 Stainless Steel
stainless steel is used as raw material and pickling in HCl-based electrolytes is adopted, and the effect of pickling temperature on removal behavior of the oxide layer on stainless steel is systematically studied, study found that the oxide layer of stainless steel after heat treatment in the lab is composed of Fe2O3 and Cr2O3, at different temperatures, with the increasing of duration, corrosion potential of stainless steel after heat treatment shows fall followed by rise, and corrosion potential of stainless steel in 60°C is obvious higher than in 50 °C; with temperature increasing, the weight loss of stainless steel after pickling increase with large range, and the weight loss of the oxide layer of stainless steel increases as the duration increases.
Hydrogen Peroxide Decomposition in an Environmentally Friendly Pickling Solution for AISI 316L Stainless Steel, January 2005
Abstract There is increasing interest in the utilization of ecological bath solutions for the pickling of stainless steel (SS), because conventional nitric (HNO3) and hydrofluoric (HF) acid mixtures generate high NOx emissions. A mixture of hydrogen peroxide (H2O2), sulfuric acid (H2SO4), and HF has been tested in this study as an environmentally friendly pickling solution for AISI 316L SS (UNS S31603). The decomposition of H2O2 and the H2SO4-HF-H2O2 mixture was assessed at different temperatures from 25°C to 60°C, with ferric ion contents from 0 to 40 g/L, with and without stirring of the aqueous acid mixture. The p-Toluene sulfonic, 3-hydroxybenzoic, and 4-dodecylbenzene sulfonic acids were tested as stabilizers for H2O2. The AISI 316LSS pickling rate found at 50°C was 2.35 × 103 mg/dm2-day (mdd) and 0.12 × 103 mdd, respectively, in the absence and presence of 40 g/L ferric ion.
Joint strength of aluminum ultrasonic soldered under liquidus temperature of Sn–Zn hypereutectic solder
Abstract In order to obtain high-strength aluminum joints, ultrasonic soldering of 1070 aluminum was conducted under liquidus temperature of Sn–Zn hypereutectic solder. A device for ultrasonic soldering was assembled, which propagated ultrasonic vibrations in a direction perpendicular to joining surfaces. This device joined 1070-Al using quasi-melting Sn–Zn hypereutectic solder without using any artificial spacers. The strength of the solder joints was evaluated by tensile tests. The optimum joining conditions were determined, and the effects of solder compositions and soldering temperature on the joint strength and the solder layer thickness were examined. In this ultrasonic soldering process, the highest tensile strength was obtained for the solder joints fabricated at 220 °C for the Sn–23Zn and Sn–40Zn solder compositions. The joint strength was equivalent to that of 1070-Al heat treated at 220 °C. The sound joints were obtained at 300 °C using Sn–82Zn solder, the liquid phase volume fraction of which was theoretically only 0.24. The present work also revealed that the thickness of retained solder layer in the joint after ultrasonic soldering could be estimated. Accordingly, ultrasonic soldering under the liquidus temperature of Sn–Zn hypereutectic solder could be a spacer-free soldering method to obtain high-strength aluminum joints.