Effect of Minor Alloying Elements (C, Ni, Cr, Mo) on the Long-Term Corrosion Behaviors of Ultrahigh-Strength Automotive Steel Sheet in Neutral Aqueous Environment

This study examined the effects of minor alloying elements (C, Ni, Cr, and Mo) on the long-term corrosion behaviors of ultrahigh-strength automotive steel sheets with a tensile strength of more than 1800 MPa. A range of experimental and analytical results showed that the addition of Ni, Cr, and Mo decreased the corrosion current density and weight loss in electrochemical and immersion tests, respectively, in a neutral aqueous condition. This suggests that the minor addition of elements to steel can result in improved corrosion resistance even for long-term immersion periods. This is closely associated with the formation of thin and stable corrosion scale on the surface, which was enriched with the alloying elements (Ni, Cr, and Mo). On the other hand, their beneficial effects did not persist during the prolonged immersion periods in steel with a higher C content, suggesting that the beneficial effects of the minor addition of Ni, Cr, and Mo were overridden by the detrimental effects of a higher C content as the immersion time was increased. Based on these results, lower C and the optimal use of Ni, Cr, and Mo are suggested as a desirable alloy design strategy for developing ultrahigh-strength steel sheets that can be exposed frequently to a neutral aqueous environment.

A Study of Programmable Logic Controllers (PLC) in Control Systems for Effective Learning

PLC controllers in today's day are a staple mechanism to control operation of large number of machines and devices in the industry. With their advanced usage, it is increasingly becoming a staple and important part of Engineering. Thus, it is crucial that this knowledge is effectively delivered to students with practical applications. This paper presents a series of laboratory experiments for students to learn and explore the various industrial applications of PLC’s. The control problems in this paper are defined with respect to their applications in different industries such as automotive, steel, oil and electronics. Applications are typical processes that can be observed in these industries such as material conveying, material handling, cutting processes, system control and temperature control. All the problems are solved using Ladder Logic programming on Automation Studio to simulate these processes and provide students with a wholesome learning experience.

A Study of Programmable Logic Controllers (PLC) in Control Systems for Effective Learning

PLC controllers in today's day are a staple mechanism to control operation of large number of machines and devices in the industry. With their advanced usage, it is increasingly becoming a staple and important part of Engineering. Thus, it is crucial that this knowledge is effectively delivered to students with practical applications. This paper presents a series of laboratory experiments for students to learn and explore the various industrial applications of PLC’s. The control problems in this paper are defined with respect to their applications in different industries such as automotive, steel, oil and electronics. Applications are typical processes that can be observed in these industries such as material conveying, material handling, cutting processes, system control and temperature control. All the problems are solved using Ladder Logic programming on Automation Studio to simulate these processes and provide students with a wholesome learning experience.

Experimental determination and numerical prediction of the dynamic forming limits of a press hardened steel

Material characteristics such as yield strength, failure strain, strain hardening and strain rate sensitivity parameter are affected by loading speed. Therefore, the strain rate dependency of materials for plasticity and failure behavior is taken into account in crash simulations. Moreover, a possibility for consideration of instability at multi-axial dynamic loadings in crash simulations is the use of dynamic forming limit curves (FLC). In this study, the dynamic FLC of the press hardened automotive steel Usibor 1500 (AlSi coated 22MnB5) is investigated. The experimental results are obtained from a unique high-speed Nakajima setup. Two models are used for the numerical prediction. One is the numerical algorithm CRACH as part of the modular material and failure model MF GenYld+CrachFEM 4.2. Furthermore, the extended modified maximum force criterion considering the strain rate effect is also used to predict the dynamic FLC. The comparison of the experimental and numerical results are presented and discussed.

Automotive Steel with a High Product of Strength and Elongation Used for Cold and Hot Forming Simultaneously

A low-cost and easy-to-produce C–Mn–Cr automotive steel for both cold and hot forming is presented in this paper. The alloying element Cr was used to replace Mn in medium-Mn steel and instead of B in hot-formed steel, in order to achieve microstructure control and hardenability improvement, replacing the residual austenite-enhanced plasticization with multidimensional enhanced plasticization through multiphase microstructure design, grain refinement, and dispersion enhancement of second-phase particles. The products of strength and elongation for the cold-formed and hot-formed steel were 20 GPa·% and 18 GPa·%, respectively, while the tensile strengths were more than 1000 MPa and 1500 MPa, respectively. This new automotive steel was also characterized by good oxidation resistance. The mechanisms of strength and plasticization of the experimental automotive steel were analyzed.