Abstract: A high toughness steel has a composition comprising, by weight, about 0.10% to 1.05% carbon, about 0.00% to 0.05% aluminum, about 0.01% to 0.20% titanium, about 0.0005% to 0.02% boron, about 0.01% to 0.20% niobium and about 0.015% to 0.04% nitrogen and the balance essentially iron. Also, the composition contains sufficient amount of manganese, silicon, nickel, chromium, vanadium, and molybdenum such that said high toughness steel article, after quenching and tempering, has a R.sub.c hardness measured in the middle of a section having a thickness of no more than 25.4 mm, of at least 50% of the hardness measured at the surface of said section. After quenching and tempering, steel articles made of this composition have a plane strain fracture toughness more than 25% higher than that for steel having the same base chemistry and heat treatment, and being free from titanium, niobium, and boron and elevated nitrogen. Also, the composition preferably contains about 0.001% to 0.004% oxygen and less than about 0.

Abstract: A recoil mechanism of an endless track of a material working machine has first and second springs of differing compression rates. After loads of impact are absorbed by compression of one of the springs, the load is shared by the other spring and a hydraulic cylinder.

Abstract: A ceramic adhesive comprises a ceramic matrix formed from a mixture of a metallic oxide and an alkali silicate in water, the ceramic matrix further having a sealed porosity, and silicon carbide whiskers dispersed within the ceramic matrix. Further, a ceramic adhesive comprises a ceramic matrix formed from a mixture of magnesium oxide in the range of about 50% to about 80% by weight and sodium silicate in water in the range of about 50% to about 20% by weight, and silicon carbide whiskers dispersed within said ceramic matrix, the whiskers being in the range of about 3% to about 25% by weight of the ceramic matrix. The porosity of the ceramic adhesive is sealed by an organic epoxy resin. A ceramic adhesive of the present invention is particularly useful in mounting and bonding in-cylinder sensors to steel internal engine parts.