Abstract: A method of determining a composition of a steel alloy includes minimizing a presence of AlN by satisfying the following condition: Al×N<5×103 (weight %), minimizing a formation of cementite by satisfying the following condition: Si+Al>4×C (weight %), wherein an Al content is selected in a range of 0.05 to 3.00 in weight %, wherein a N content is selected in a range of 0.001-0.025 in weight %, wherein a Si content is selected in a range of 0.25-4.00 in weight %, wherein a C content is selected in a range of 0.1-0.70 in weight %.

Abstract: A low alloy high-strength carbide-free bainitic steel for producing strips, sheets and pipes is disclosed with the following chemical composition (in weight %) 0.10-0.70 C, 0.25-4.00 Si, 0.05-3.00 Al, 1.00-3.00 Mn, 0.10-2.00 Cr, 0.001-0.50 Nb, 0.001-0.025 N, max 0.15 P, max 0.05 S, remainder iron and steel tramp elements with optional addition of one or more elements of Mo, Ni, Co, W, Nb, Ti, or V and Zr and rare earths with the proviso the for avoiding primary precipitations of AlN the condition Al×N<5×10?3 (weight %) and for suppressing the cementite formation the condition Si+Al>4×C (weight %) are satisfied.

Abstract: In a method of making a high-pressure accumulator pipe as composite pipe of steel for pressures of up to 1800 bar and above with high static strength and fatigue strength for fuel injection systems with common rail systems for internal combustion engines, a first inner pipe part is inserted into a second outer pipe part with little clearance, and the inner pipe part is connected to the outer pipe part gap-free and by interference fit through mechanical forming. The mechanical forming includes a rolling-in process, wherein the inner pipe part is subjected to a ductile expansion and the outer pipe part is subjected to an elastic expansion using an oversized rolling tool that is moved within the inner pipe part, and wherein a residual compressive stress adjusted to the operating pressure is applied to the inner pipe part after the forming process via the elastic resilience of the outer pipe part.