From rubber material to diamond layer coating: New and precise test method analyzes strength of surfaces and strength distribution within mono layers and multi layers

Resistance against gouging and abrasive wear in impact crushing arms cast from Mn-steel, is related to variations of carbon, manganese and the microstructure of the cast steel. Additions of Boron, molybdenum and chromium to the plain Mn-steel casts (0.8-1.4%C-13%Mn) increase its wear resistance and fatigue life time during crushing operation due to enhancement of its strain hardeing capacity, grain refinement and strengthening by solid solution hardening of the matrix. This improvement is due to the intended change in the microstructure where precipitation of boron carbides and chromium carbides inside the austenitic matrix, grain refinement and increasing soluble carbon content in austenite phase is occurred. Solution treated Mn-steels (1050C, 2h, WQ) alloyed with boron showed crushing capacity of about 1200-1550 tones basalt per set depending on their compositions. The hardness of the as water quenched austenite is increased by about 25% to reach 397 HB when alloyed with 0.37%B. However work hardened matrix of Cr+Mo+B modified Mn-steel impact arms showed a bulk hardness of about 498 HB. The fatigue resistance of boron alloyed steel is increased to about 1.4 times over that measured for plain Mn-steel.

Chips of various morphologies formed during surface grinding of cast AISI 409 stainless steel slabs have been examined in light microscope and SEM. Dynamic nucleation of fresh grains occur in the work hardened layer of chips of various morphologies, but growth of these grains on the chip surface is highly non-uniform. Iron rich oxide nodules also grow on the chip surface.

Enameling steel has important applications in our daily life as in domestic appliances and industry (chemical, agro-food, storage tanks, heat exchangers..etc.) due to its outstanding properties resulting from combined advantages of steel and enamel. The combination of such steel and enamel provides durability and glossy appearance that withstand chemical corrosion, abrasion, thermal shocks and fire. The durability and quality of enameling process depends to a great extent on the quality of substrate (enamel steel). To ensure an acceptable quality of such steel to be enameled, care must be taken during steelmaking and refining such grade to obtain low carbon levels (0.03-0.05%max) and minimum count of inclusions. The morphology of inclusions is adjusted by Ca-cored wire feed technology however melt stirring using Argon is very useful to minimize inclusions and gas contents. Vacuum decarburization of steel melt to ensure low carbon levels prevents the black specks during firing of such steel sheets; however micro-alloying with 0.2-0.5% Ti or V stabilizes the rest of carbon and creates default sites for hydrogen after cold rolling to prevent fish scale phenomena after enameling. Assessment of inclusion counts and their morphology as well as distribution of carbides are carried out using scanning field electron microscopy and ASTM standard.

Continuous casting, initially introduced in 1840, is an attractive method in mass producing semi-finished metal shapes (slabs, blooms, and billets) from molten metal. More than 50% of current world’s steel production is produced by continuous casting. Today, annually 750 million tons of steel in the steelmaking operation, 20 million tons of aluminum and many tons of other alloys are directly cast from molten metal by continuously casting method [1]. This paper presents a short review over the processes in consciously cast steel.