Outer ring for an oil pump and a method for manufacturing the same

A method for manufacturing an outer ring for an oil pump, the method comprising:

• mixing a pre-alloy powder with a copper mixture to prepare a mixed powder;
• compacting the mixed powder into a compact;
• sintering the compact to prepare a sintered body;
• and
• sinter hardening the sintered body,
• wherein the pre-alloy powder comprises:
• 1.35 wt. % to 1.65 wt. % of chromium;
• 0.16 wt. % to 0.24 wt. % of molybdenum;
• 0.10 wt. % to 0.25 wt. % of manganese;
• and
• a balance of iron, and
• wherein the copper mixture comprises:
• 15 wt. % to 18 wt. % of carbon;
• 8 wt. % to 9 wt. % of manganese sulfide;
• 55 wt. % to 57 wt. % of copper;
• and
• 19 wt. % to 20 wt. % of a lubricant.