An Overview of Practicability and Application of 300M Steel in the Face of Stress Corrosion Cracking Issue

Abstract

The paper highlights 300M steel as an engineering material that is commonly used in special applications where fracture toughness, ductility, and ultra-high strength in the 2000-2070MPa range is required such as aircraft landing gear, airframe parts, undercarriage components, gears, shafts, and bolts. Stress corrosion cracking (SCC) is recapitulated as the drawback of the steel in its service applications. The aim of the paper is to call attention to the SCC problem and highlight the pros and cons of the existing alleviation methods for better appreciation of the way forward. The overview indicates interminable positive research inputs in alleviating SCC of the steel in its service applications by; use of coatings, heat and surface-treatments, inducement of surface compressive stresses, design techniques, and cathodic protection. It is however seen that SCC alleviation of the steel has not yet reached ideal level due to some impracticability and cost implications in using the SCC control methods in many cases, and no better alternative material has been found for the steel. Only few research inputs on the numerous environmental types that the steel can be in service contact with are found in the literatures for its SCC alleviation. Improving practicability and versatility of the existing SCC alleviation methods and optimization of SCC-susceptibility test information of the steel from much larger number of the environmental types and their various levels of combinations are deemed needful towards ideal SCC alleviation of the steel

Development of Bituminous Paint from Agbabu Natural Bitumen for Coat Coat-Protecting the Underparts of Automobile Chassis against Corrosion and Wear

“…11. Generally, mild steel corrosion rates of less than 1.3 mm/yr are considered good corrosion control in atmospheric environments [5]. From these results, it is inferable that the coating of the paint blends provided satisfactory protection of the steel in all cases, and the paint blend that contained 75% of the natural bitumen has higher protection potential against corrosion and wear of mild steel than all the other paint blends.…”

“…4, 5]. The critical causes of vehicular corrosion are road debris, sand, gravel, and, most importantly, deicing materials that sandblast its body, especially the underbody or chassis [5]. These actions leave chips in the protective coatings of the vehicles and predispose the undercoat substrate and other exposed parts to corrosive atmospheric moisture and severe temperatures [5].…”

“…The critical causes of vehicular corrosion are road debris, sand, gravel, and, most importantly, deicing materials that sandblast its body, especially the underbody or chassis [5]. These actions leave chips in the protective coatings of the vehicles and predispose the undercoat substrate and other exposed parts to corrosive atmospheric moisture and severe temperatures [5]. The combined corrosive actions of atmospheric moisture and chemical compounds such as chlorides, sulfur oxides, nitrogen oxides, carbon oxides, and acidic substances further contribute to the breakdown or deterioration of the exposed areas of auto-body parts.…”

“…The combined corrosive actions of atmospheric moisture and chemical compounds such as chlorides, sulfur oxides, nitrogen oxides, carbon oxides, and acidic substances further contribute to the breakdown or deterioration of the exposed areas of auto-body parts. Exposed areas of the front understructure, suspension and axle assembly, rear frames, gussets, rear underride guards, front aprons, threshold plates, upper couplers, and main frame assembly are typically affected by environmental chemicals and sandblasting [5]. As an automobile is driven over various distances from time to time for many years in different climatic regions and road conditions, carrying people and/or loads, its structural components, especially the underpart of its chassis, can experience significant corrosion and wear [6,7,8].…”

“…Most autobody parts are protected and regularly maintained against wear and corrosion, but the chassis is much more difficult and expensive to protect and maintain against corrosion and wear due to accessibility difficulties to it, cost of painting it, and the general infeasibility or impracticability of other protective methods such as cathodic or anodic protection, use of inhibitors, and use of metallic and inorganic coatings for automobile body parts [5,9]. Protecting an automobile against corrosion and wear is crucial for its overall longevity and aesthetic and financial value.…”