Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : AISI

Corrosion Resistance Enhancement in Acidic solution for Austenitic Stainless Steel by Gas-Phase Hybrid Deposition Process

A.D. Thamir; F.Q. Mohammed; A.S. Hasan; A.L. Abid

Engineering and Technology Journal, 2017, Volume 35, Issue 8, Pages 788-794

In acidic environments the corrosion rate of stainless steels is considered high, this is due to pitting occurrence in concentrated chloride environments. The Austenitic steels such as type 316 stainless steel generally not recommended for Hydrochloric acid storage in petroleum planets except when solutions are very dilute and at room temperature, otherwise pitting may occur. In this work, a multicomponent coating (Ti-B-N-C) was deposited on the austenitic stainless steels (AISI 316) that used in petroleum industry. The coating process has been achieved by mixed vapor deposition technique; this was done in attempt to improve the resistance to pitting corrosion for austenitic stainless steels surface. The structural characterization for the deposited Ti-Base coating was done by using XRD technique, and the Scanning Electron Microscopy (SEM). Electrochemical corrosion tests have been performed by using electrochemical test in 0.25M hydrochloric acid (HCl) as an aqueous solution at 22˚C to obtain the anodic polarization curves for the coated surfaces. Several interesting observations have been made During the test. As expected, the surface of the AISI 316 suffers from a sudden increase in the current density at the potential above 1500 mV due to the occurrence of pitting corrosion. In addition, the Ti-B-C-N coating surfaces show great future in reducing the current density of the steel surface in the anodic region, indicating improved pitting resistance for all Ti-based coating samples. No evidence for pitting corrosion was observed in the coated surfaces during electrochemical test even at potentials up to 2000 mV, instead, general corrosion was observed for the samples that was deposited at 750˚C since low potential values was observed for these samples .

Effect of laser surface treatment on the some of mechanical properties of AISI 4130 steel

J.M. Taha

Engineering and Technology Journal, 2017, Volume 35, Issue 2, Pages 85-90

In this work the surface of an alloy of AISI 4130 steel is hardened by using CW Nd:YAG laser and then study the effect of laser surface hardening on mechanical properties such as yield strength (σy), ultimate tensile strength (σu.T.S), plasticity constant (k),strain hardening coefficient (n) , also evaluate the microstructure and microhardness during the hardening of the alloy. CW Nd:YAG laser was used to scan on the surface of samples by varying the laser beam energies (500,750,1000 mj) with travel speed 500 mm/min of the work table. There are many examinations were done for laser hardened of AISI 4130 steel such as an analysis of microstructure features by using an optical microscopy and microhardness. Also tensile test is carried out for the specimens before and after laser surface treatment. The results of this investigation showed that an improvement in mechanical properties after laser surface hardening, also microhardness decreases faraway the hardened surface toward the center of the specimen. While the microstructure examination showed that the laser energy 1000 mj lead to form fine plate martensite structure more than another energies 500 and 750 mj.

Optimization of Hot-Dip Aluminizing Process Parameters of AISI 303 Stainless Steel Using RSM

Ahmed Naif Al-Khazraji; Samir Ali Al-Rabii; Hameed Shamkhi Al-Khazalli

Engineering and Technology Journal, 2015, Volume 33, Issue 9, Pages 2130-2145

The coating thickness is an important factor to evaluate the coating quality and determining the properties of the hot-dip aluminizing (HDA)coating. In the present work, a hot dipping pure aluminum (99%) on stainless steel (AISI 303) rods was carried out for different diameters of rods (8, 10 and 12mm) and different lengths (250 and 500 mm) at different aluminizing conditions of temperature and time. The dipping temperature was set to 700, 740, 780, 820 and 860℃ .The dipping time was set to 1, 2, 3,4 and 5 minutes. A response surface methodology (RSM) using a central composite rotatable design (CCD) for a 2³ factorial, with 5 central points and α = ±2 approach, based on the experimental data, was used to obtain the optimum modelto get the best thickness of coating and the best conditions of dipping. A 2nd polynomial model was obtained with a confiding percentage of 95%.Analysis of the experiments using RSM indicated that 807℃ and3minare optimum dipping conditions for hot-dip aluminizing process with corresponding thickness of coating layers of 134 μmto Al layer,62.9 μm to intermetallic compound (IMC) layer and 197μm to total coating layer.

Effect of Nickel Coating on Fatigue Resistance of Carburized AISI 301 Stainless Steel

Moayad Abdullah Mohammad; Jamal Nayief Sultan; Suhaila Younis Hussain; George Matti Hanosh

Engineering and Technology Journal, 2014, Volume 32, Issue 1, Pages 13-23

The present research deals with the study of the effect of Nickel Coating on the fatigue resistance of carburized and uncarburized AISI 301 stainless steel. Six groups of bending fatigue specimens were prepared for fatigue test.
Two groups of the carburized specimens were precoated with Nickel. The Nickel coated specimens were then case carburized at a temperature of (540°C) for 90 minute. The other Nickel coated specimens were then case carburized at a temperature of (950°C) for 120 minute.
Experimental results revealed an increase in fatigue resistance by (25%) for Nickel coated specimens which are carburized at low temperature of (540°C) as compared with the as received specimens.
The surface hardness was increased by 79.4% for those specimens that have been carburized at a temperature of (540°C), while the specimens that have been coated by Nickel then carburized at low temperature of (540°C) showed a 34.3% increase in surface hardness.