METHOD OF MANUFACTURING STEEL MECHANICAL PARTS AND STEEL FOR MANUFACTURING SAID PARTS Russian patent published in 2003 - IPC

FIELD: metallurgy. SUBSTANCE: method involves manufacture of steel blank of a part, its treatment by cementation or carbonitridation (cyanidation), optionally at high temperature, steel is composed, wt.%: carbon, 0.15-0.35; silicon, at most 0.6; sum of manganese, chromium, and molybdenum, at most 5.0; aluminum, at most 0.1; copper, at most 0.5; sulfur, at most 0.15; phosphorus, at most 0.03; and optionally up to: tellurium, 0.02; selenium, 0.04; lead, 0.07; and calcium, 0.005; iron, the balance. Jominy hardenability for said steel should meet following conditions: 45HRC ≤J₃≤ 50HRC, 39HRC ≤J₁₁≤ 47HRC, 31HRC ≤J₂₅≤ 40HRC. Average values J_3av, J_11av, J_15av, and J_25av of five Jominy bars must satisfy following conditions: |J_11av-J_3av•14/22-J_25av•8/22|≤ 2.5HRC, J_3av-J_15av≤ 9HRC. EFFECT: enabled manufacture of steel parts without deformation and hogging upon tempering after high-temperature cementation or carbonitridation. 15 cl, 4 tbl, 6 ex