Improvement of Aluminum Erosion Behavior and Corrosion Resistance of AISI H13 Tool Steel by Oxidation Treatment

Abstract

In this work, H13 tool steel was prepared with different oxidation treatments to investigate the effects of oxidation temperature and soaking time. In order to improve erosion and corrosion resistance, this study tested with oxidation temperatures of 560°C, 580°C, and 600°C, and oxidation soaking times of 1 h, 2 h, and 3 h, respectively. Experimental results showed that the oxidation treatment at 600°C and for 3 h is the optimum process. The average thickness of the oxide layer was 9.2 mm. It showed that the oxide layer (Fe 3 O 4 ) can protect and improve the aluminum erosion of H13 steel. The specimens that underwent the oxidative procedure were proven to effectively reduce the ratio of Al-Fe-Si compounds during erosion tests of A380 alloy solution. In addition, the results showed that the oxide layer can enhance polarization resistance, and quickly generate a passivation layer to increase the ability of corrosion resistance.KEY WORDS: H13 tool steel; erosion; corrosion; oxidation; A380 alloy. 569© 2010 ISIJ in order to enhance the erosion rate and weight loss. After removing the aluminum, specimens were cleaned with NaOH to remove any oxide or other residue. The weight loss percentage of erosion test is calculated as follows:Weight loss (%)ϭ(IWϪAW)/IWϫ100 IW is the initial weight, and AW is the weight after erosion test.Corrosion potential analysis adopted three electrodes method. Reference electrode was saturated with silver-silver chloride electrode, auxiliary electrode was a Platinum electrode, and working electrode was connected to the testing specimens. The contact area of specimen was 2.01 cm 2 . Meanwhile, the corrosive solvent used 3.5 wt% NaCl, and was kept at room temperature. The main parameters of corrosion testing included: scanning speed of 0.5 mV s Ϫ1, initial potential of Ϫ1.5 V, and the final potential of 0.5 V. The polarization curve was obtained by Corr-View software for analysis, and compared with different oxidation parameters of the corrosion potential (E corr ) and corrosion current (I corr ). Finally, the polarization resistances (R p ) of different oxidation treatments for AISI H13 tool steel were compared. To evaluate the improvement in erosion and corrosion resistance of AISI H13 tool steel via different oxidation processes, erosion and corrosion tests, XRD and EDS, and microstructure inspections were performed. Figure 3 shows the XRD patterns of H13 tool steel after 560°C 1 h, 2 h, and 3 h of oxidation treatment. As seen, the strongest peak is the original a-Fe structure, in addition, there are two other different crystal structures, Obviously, at the same temperature and different soaking times of oxidation treatment, XRD analysis indicated that two different kinds of oxide layers were provided after oxidation treatments, which are the crystal structures of Fe 3 O 4 and Fe 2 O 3 . The intensity of the original a-Fe gradually decreased as the soaking time of oxidation increased, indicating that increasing the soaking time of oxidation would reduce the proportion of the a-Fe structur...

Change in Microstructure, Mechanical Strength and Corrosion Resistance of Ti-8Mo-xNi Alloys through Various Sintering Temperatures

“…25,26) Our previous study showed that the passivation probability in −0.4 −1.0 V crosses a potentially large range. 27) In this study, there was a slight change in the corrosion potential of the Ti-8Mo-xNi specimens, and the corrosion current varied through the different sintering temperatures and Ni contents after the corrosion tests. A lower corrosion current appeared at the 1175 C sintering temperature.…”

Effects of Thermal Erosion and Wear Resistance on AISI H13 Tool Steel by Various Surface Treatments

“…Another factor is the Fe element that escapes from matrix, while combined with aluminum and silicon elements to generate the Fe x Al y Si z compound at the interface during the erosion test processes. 6) Significantly, the columnar structure of CrN-H13 specimen seems can effectively inhibit the formation of Fe x Al y Si z compound after 4 h corrosion test. However, it will gradually reduce the corrosion resistance after a longer test (5 h).…”

“…6) Figure 3(a) shows the microstructure of a cross-section of O-H13 specimens where the depth of the oxynitriding layer is about 75 « 1 µm; and the EDS analysis (see Table 3) of a, b, and c are the coated Ni layer, Fe oxides, and the nitriding layer, respectively. Due to the outermost layer of gray oxynitriding film is very thin (12 µm) and hard to find it.…”

“…To extend die-casting die life, different thermo-chemical treatments are often applied to the die surface. Our previous study 6) found that oxynitriding specimens could form a passive film, which contributed a better anti-corrosion property during the corrosion test.…”

“…During filling, solidification and the die holding stages, the molten aluminum attacks the die steel surface. 6) AISI H13 tool steel is normally used for Al die-casting dies, given its good temperature resistance, high hardness, and good resistance to thermal fatigue, erosion and wear. To extend die-casting die life, different thermo-chemical treatments are often applied to the die surface.…”