Abstract: A ferrous alloy suitable for use as a knife in a rotary wood chipper, said alloy consisting essentially of, by weight,______________________________________ Broad (%) Preferred (%) ______________________________________ Carbon .40-.60 .45-.50 Manganese 1.0 max. .20-.40 Phosphorus 0.035 max. 0.025 max. Sulfur 0.035 max. 0.025 max. Silicon 1.50 max. .30-.50 Nickel 2.00 max. .25-.35 Chromium 4.0-6.0 4.6-4.8 Molybdenum 1.0-3.0 1.9-2.1 Aluminum 0.10 max. 0.010-0.030 Iron* balance balance ______________________________________ *includes optional additions in nominal amounts of columbium, titanium, vanadium, tungsten, cobalt.The alloy, in a heat-treated condition, is characterized by (1) a high level of toughness on the order of 100 ft-lbs min. on unnotched specimens, (2) good wear resistance, (3) good machinability, (4) a hardness of at least 56 HRC after a double temper at 950.degree. F. or higher, and (5) being hardenable using a maximum of 1850.degree. F. as the austenitizing temperature.

Abstract: A ferrous alloy suitable for use as a knife in a rotary wood chipper, said alloy consisting essentially of, by weight,______________________________________ Broad (%) Preferred (%) ______________________________________ Carbon .40-.60 .45-.50 Manganese 1.0 max. .20-.40 Phosphorus 0.035 max. 0.025 max. Sulfur 0.035 max. 0.025 max. Silicon 1.50 max. .30-.50 Nickel 2.00 max. .25-.35 Chromium 4.0-6.0 4.6-4.8 Molybdenum 1.0-3.0 1.9-2.1 Aluminum 0.10 max. 0.010-0.030 Iron* balance balance ______________________________________ *includes optional additions in nominal amounts of columbium, titanium, vanadium, tungsten, cobalt.The alloy, in a heat-treated condition, is characterized by (1) a high level of toughness on the order of 100 ft-lbs min. on unnotched specimens, (2) good wear resistance, (3) good machinability, (4) a hardness of at least 56 HRC after a double temper at 950.degree. F. or higher, and (5) being hardenable using a maximum of 1850.degree. F. as the austenitizing temperature.

Abstract: A ferrous alloy suitable for use as a knife in a rotary wood chipper, said alloy consisting essentially of, by weight,______________________________________ Broad (%) Preferred (%) ______________________________________ Carbon .40-.60 .45-.50 Manganese 1.0 max. .20-.40 Phosphorus 0.035 max. 0.025 max. Sulfur 0.035 max. 0.025 max. Silicon 1.50 max. .30-.50 Nickel 2.00 max. .25-.35 Chromium 4.0-6.0 4.6-4.8 Molybdenum 1.0-3.0 1.9-2.1 Aluminum 0.10 max. 0.010-0.030 Iron* balance balance ______________________________________ *includes optional additions in nominal amounts of columbium, titanium, vanadium, tungsten, cobalt.The alloy, in a heat-treated condition, is characterized by (1) a high level of toughness on the order of 100 ft-lbs min. on unnotched specimen, (2) good wear resistance, (3) good machinability, (4) a hardness of at least 56 HRC after a double temper at 950.degree. F. or higher, and (5) being hardenable using a maximum of 1850.degree. F. as the austenitizing temperature.

Abstract: A die steel having high hardenability, high hardness, good toughness and capable of achieving a high polished surface flatness in the air or oil quenched and tempered condition. Such steel is ideally suited as a die steel for lens quality and photo-etching applications. The unique combination of properties is accomplished through a careful balancing of the chemistry, particularly control of those elemental additions which promote segregation. Within the broad chemistry limits, by weight, of carbon 0.3 to 0.8%, and the maximum quantities of manganese 3.0%, phosphorus 0.025%, sulfur 0.025%, silicon 2.0%, nickel 4.0%, cobalt 4.0%, chromium 3.0%, vanadium 1.0%, molybdenum 1.5%, tungsten 1.5%, niobium 0.1%, titanium 0.5%, aluminum 0.10%, optionally boron between 0.0005 and 0.012%, balance iron, the desired polishability can be achieved through adherence to the equation:Surface Roughness (.mu.-inch)=Boron factor [7.07-12.5(% C)+0.72(% Mn)+0.45(% Si)-2.9 (% Ni)+1.13(% Ni).sup.2 +0.87(% Cr)+2.1(% V)+1.12 (% Mo)+0.