Disclosed are an outer ring for an oil pump having an increased number and size of open pores in a surface of a molded article and a method for manufacturing the outer ring.

A composite cemented carbide roll comprising an inner layer made of an iron-based alloy, and an outer layer made of cemented carbide which is metallurgically bonded to an outer peripheral surface of the inner layer; the cemented carbide of the outer layer comprising 55-90 parts by mass of WC particles and 10-45 parts by mass of an Fe-based binder phase having a particular composition; a shaft member and a shaft end member being metallurgically bonded to at least one axial end of the inner layer; the inner layer being made of an iron-based alloy containing 2.0% or more in total by mass of at least one selected from the group consisting of Cr, Ni and Mo; and the shaft member and the shaft end member being made of an iron-based alloy containing 1.5% or less in total by mass of at least one selected from the group consisting of Cr, Ni and Mo.

A gear includes a sintered body, in which Fe is contained as a principal component, Ni is contained in a proportion of 2 mass % or more and 20 mass % or less, Si is contained in a proportion of 0.3 mass % or more and 5.0 mass % or less, C is contained in a proportion of 0.005 mass % or more and 0.3 mass % or less, and one element selected from the group consisting of Ti, V, Y, Zr, Nb, Hf, and Ta is defined as a first element, that is contained in a proportion of 0.01 mass % or more and 0.7 mass % or less.

A method for a workpiece comprising a material composed of a base material and an additive is disclosed, the method including spreading a granular material in superimposed layers. The granular material contains the base material and an organic binder. An ink contains a solvent for dissolving the binder, and a suspension of the additive. Using the ink, patterns are printed onto individual layers. The ink dissolves the binder in the region of the patterns, and introduces the additive in the region of the patterns. The patterns in the layers together produce a three-dimensional shape of the workpiece. The solvent is expelled so that the granular material is connected by the binder and the additive is fixed. Granular material unwetted by the solvent is removed to reveal the green compact of the workpiece. The green compact is thermally treated to convert the base material and the additive into the material.

An iron-based sintered alloy material having, at the surface of the material, a hardened layer exhibiting a martensite phase containing a solid solution of nitrogen in a supersaturated state. The iron-based sintered alloy material may contain at least one of chromium, copper, molybdenum, manganese and nickel. A production method for the iron-based sintered alloy material includes: subjecting an iron-based sintered alloy substrate containing carbon to a nitriding treatment by heating the substrate to a nitriding temperature of at least 590° C. in an atmosphere containing ammonia, and then performing quenching by rapidly cooling the substrate.

An iron-based sintered alloy material having, at the surface of the material, a hardened layer exhibiting a martensite phase containing a solid solution of nitrogen in a supersaturated state. The iron-based sintered alloy material may contain at least one of chromium, copper, molybdenum, manganese and nickel. A production method for the iron-based sintered alloy material includes: subjecting an iron-based sintered alloy substrate containing carbon to a nitriding treatment by heating the substrate to a nitriding temperature of at least 590° C. in an atmosphere containing ammonia, and then performing quenching by rapidly cooling the substrate.

The present disclosure relates to an iron-based prealloy powder having excellent strength and processability, and an iron-based alloy powder for powder metallurgy and a sinter-forged member using the same. The iron-based prealloy powder for powder metallurgy according to an embodiment of the present disclosure includes 0.5 to 5.0 wt % of Cu, 0.1 to 0.5 wt % of Mo, and a balance of Fe and other inevitable impurities. A Cu content (Cu %) and a Mo content (Mo %) satisfy the following Relational Equation (1):
0.3×Cu %+3×Mo %≤2.7  (1).

The present disclosure relates to an iron-based prealloy powder having excellent strength and processability, and an iron-based alloy powder for powder metallurgy and a sinter-forged member using the same. The iron-based prealloy powder for powder metallurgy according to an embodiment of the present disclosure includes 0.5 to 5.0 wt % of Cu, 0.1 to 0.5 wt % of Mo, and a balance of Fe and other inevitable impurities. A Cu content (Cu %) and a Mo content (Mo %) satisfy the following Relational Equation (1):
0.3×Cu %+3×Mo %≤2.7  (1).

An apparatus and method for manufacturing iron-based mixed powder with excellent flowability is provided. The apparatus includes a hopper which stores and discharges a main raw material of iron-based powder, a transport means which transports the main raw material of iron-based powder discharged from the hopper, a magnetizing means that applies magnetic force to the main raw material transported and falling from the transport means to process the main raw material of iron-based powder into a main raw material bundle in a crumbly type in which the main raw material of iron-based powder is agglomerated with each other, a first mixer in which the main raw material bundle in a magnetized state and an auxiliary raw material of iron-based powder are loaded and mixed while being rotated and transported, and a second mixer in which a first iron-based mixed powder is mixed while being rotated and transported.

A method for producing a sintered component, in particular an annular sintered component, with a toothing, having teeth with tooth roots, tooth tips and tooth flanks, includes the steps of pressing a powder to form a green compact, sintering the green compact, and hardening the sintered component, wherein after sintering, the tooth flanks and possibly the tooth tips are post-compacted and subsequently undergo post-processing by machining, and wherein a transition region between the tooth flanks and the tooth roots has an undercut design, and post-compaction of the tooth flanks is carried out only up to this transition region.