Material and method for the production of material with isotropic, mechanical properties and improved wear resistance and high hardness potential. Method includes producing in a powder metallurgical (PM) method a slug or ingot from a material of ledeburite tool steel alloy, and subjecting one of the slug or ingot or a semi-finished product produced from the slug or ingot to full annealing at a temperature of over 1100 C., but at least 10 C. below the fusing temperature of the lowest melting structure phase with a duration of over 12 hrs. In this manner, an average carbide phase size of the material is increased by at least 65%, a surface shape of the material is rounded and a matrix is homogenized. Method further includes subsequently processing the material into thermally tempered tools with high wear resistance occurs or into parts to which abrasive stress is applied.

A hollow screw and related process of making is provided, wherein the hollow screw is formed from a generally circular corrosion resistant stainless steel disk cut from flat roll stock. The hollow screw includes a head and an elongated and hollow shaft having a wall thickness between about 0.2 to about 0.7 millimeters extending therefrom and defining a shank portion and a threaded portion having a plurality of threads thereon with a rotational drive mechanism configured to facilitate tightening via the threads. The process involves annealing to soften the stamped hollow screw, followed by thread rolling, and then age hardening the hollow screw. As such, the resultant hollow screw is relatively lightweight, about 50% the mass of a solid core screw made from the same material, with a sufficient thread strength to meet most aerospace applications and contributes to important aircraft fuel economy.

A hollow screw and related process of making is provided, wherein the hollow screw is formed from a generally circular corrosion resistant stainless steel disk cut from flat roll stock. The hollow screw includes a head and an elongated and hollow shaft having a wall thickness between about 0.2 to about 0.7 millimeters extending therefrom and defining a shank portion and a threaded portion having a plurality of threads thereon with a rotational drive mechanism configured to facilitate tightening via the threads. The process involves annealing to soften the stamped hollow screw, followed by thread rolling, and then age hardening the hollow screw. As such, the resultant hollow screw is relatively lightweight, about 50% the mass of a solid core screw made from the same material, with a sufficient thread strength to meet most aerospace applications and contributes to important aircraft fuel economy.

Provided is a steel for carbonitrided bearing which excels in hardenability and also excels in toughness, wear resistance, and surface-originated flaking life after quenching and tempering. A steel for carbonitrided bearing of the present embodiment has a chemical composition containing, in mass %, C: 0.22 to 0.45%, Si: not more than 0.50%, Mn: 0.40 to 1.50%, P: not more than 0.015%, S: not more than 0.005%, Cr: 0.30 to 2.0%, Mo: 0.10 to 0.35%, V: 0.20 to 0.40%, Al: 0.005 to 0.10%, N: not more than 0.030%, and O: not more than 0.0015%, with the balance being Fe and impurities, and satisfying Formulae (1) and (2).

1.20<0.4Cr+0.4Mo+4.5V<2.60(1)

2.7C+0.4Si+Mn+0.8Cr+Mo+V>2.20(2)

Provided is a carbonitrided bearing part which has high hardenability and toughness, and is excellent in wear resistance and surface-originated flaking life. A carbonitrided bearing part of the present embodiment has a chemical composition containing, in mass %, C: 0.15 to 0.45%, Si: not more than 0.50%, Mn: 0.40 to 1.50%, P: not more than 0.015%, S: not more than 0.005%, Cr: 0.30 to 2.0%, Mo: 0.10 to 0.35%, V: 0.20 to 0.40%, Al: 0.005 to 0.10%, N: not more than 0.030%, and O: not more than 0.0015%, with the balance being Fe and impurities, and satisfying Formulae (1) and (2). At surface, C concentration is 0.7 to 1.2%, N concentration is 0.15 to 0.6%, and Rockwell hardness HRC is 58 to 65.

1.20<0.4Cr+0.4Mo+4.5V<2.60(1)

2.7C+0.4Si+Mn+0.8Cr+Mo+V>2.20(2)

In an Ag, Cu, Ge alloy containing boron as grain refiner, investment castings of a clean bright silvery appearance and/or free from cracking defects are obtained by incorporation of silicon, in some embodiments in the absence of added zinc.

A precipitation hardening type martensitic stainless steel of an embodiment contains: Cr: 8.5 to 12.5%; Mo: 1 to 2%; Ni: 8.5 to 11.5%; Ti: 0.6 to 1.4%; C: 0.0005 to 0.05%; Al: 0.0005 to 0.25%; Cu: 0.005 to 0.75%; Nb: 0.0005 to 0.3%; Si: 0.005 to 0.75%; Mn: 0.005 to 1%; and N: 0.0001 to 0.03% by mass, and the balance of Fe and unavoidable impurities.

A precipitation hardening type martensitic stainless steel of an embodiment contains: Cr: 8.5 to 12.5%; Mo: 1 to 2%; Ni: 8.5 to 11.5%; Ti: 0.6 to 1.4%; C: 0.0005 to 0.05%; Al: 0.0005 to 0.25%; Cu: 0.005 to 0.75%; Nb: 0.0005 to 0.3%; Si: 0.005 to 0.75%; Mn: 0.005 to 1%; and N: 0.0001 to 0.03% by mass, and the balance of Fe and unavoidable impurities.

A rolled steel sheet or blank is provided, the composition of which comprises the elements listed below in percent by weight: C0.1%; 0.5%Mn7%; 0.5%Si3.5%; 0.5%<Ti2%; 2%<Ni7%; Al0.10%; Cr2%; Cu2%; Co2%; Mo2%; S0.005%; P0.03%; Nb0.1%; V0.1%; B<0.005%; N0.008%, and the silicon and titanium contents are such that: $\mathrm{Si}+\mathrm{Ti}2.5\%,\frac{\mathrm{Ti}}{\mathrm{Si}}0.3$
the remainder of the composition consisting of iron and unavoidable impurities resulting from processing. A method for the fabrication of a part for a land motor vehicle from the sheet or blank by hot stamping is also provided. The microstructure of the part consisting essentially of martensite and intermetallic precipitates of type Fe.sub.2TiSi with an area percentage between 1 and 5% intermetallic precipitates.

A rolled steel sheet or blank is provided, the composition of which comprises the elements listed below in percent by weight: C0.1%; 0.5%Mn7%; 0.5%Si3.5%; 0.5%<Ti2%; 2%<Ni7%; Al0.10%; Cr2%; Cu2%; Co2%; Mo2%; S0.005%; P0.03%; Nb0.1%; V0.1%; B<0.005%; N0.008%, and the silicon and titanium contents are such that: $\mathrm{Si}+\mathrm{Ti}2.5\%,\frac{\mathrm{Ti}}{\mathrm{Si}}0.3$
the remainder of the composition consisting of iron and unavoidable impurities resulting from processing. A method for the fabrication of a part for a land motor vehicle from the sheet or blank by hot stamping is also provided. The microstructure of the part consisting essentially of martensite and intermetallic precipitates of type Fe.sub.2TiSi with an area percentage between 1 and 5% intermetallic precipitates.