About QRO-90 is a high life chromium - molybdenum - vanadium alloy hot toolbox, with uniform machinability; good heat treatment properties. Chemical composition Carbon C: 2.05 Si Si: 0.3 Mn Mn: 0.8 Cr Cr: 12.5 W tungsten characterized by excellent high temperature strength and high hardness; very good resistance to temper softening ability; unique thermal fatigue; excellent thermal conductivity ; longitudinal and transverse toughness and good ductility; die life Uddeholm QRO-90 is specially developed for the promotion of advanced thermal hot work die steel die life. The so-called "advanced" because of the use of special techniques, such as ESR steel in order to obtain high purity and good mechanical properties of steel, in conjunction with the most appropriate deployment of components, making QRO 90 properties in hot work tool steels, very unique, along with excellent high temperature strength, temper softening resistance and thermal conductivity. Thus QRO 90 can extend die casting non-ferrous metals, extrusion, forging die life, and forged iron material, extrusion die life. 1 Purpose) casting molds and related parts and components extrusion die forging die: Long life QRO-90 tool steel on aluminum, brass and copper die-casting mold life, usually hot than the average, and its excellent high temperature strength inhibition of thermal fatigue cracking, extend die life. Its high thermal conductivity can be shortened molding time and increase productivity. QRO-90 can be used in the required resistance to thermal fatigue cracking, corrosion and bending of parts, such as the core, the heart tip, embedded blocks, small and medium sized molds, feeding tubes, and other moving parts aluminum, brass, copper casting mold. QRO-90 pre-hardening process to HRC37-40 (QRO-90HT) can be directly used for casting molds mandrel 2) extrusion mold and parts:. QRO-90 is recommended for use in the production quantity needs may be greater than the general life of the aluminum mold steel the extrusion mold, such as: the need for more than a pair of high life simple shape of the extrusion die mold; complex shape, flesh thin mold; hollow mold; hard alloy extrusion. Aluminum, iron extrusion extruder parts such as Jane bushing material, pressure head, heart rod, pole, etc. lining. QRO-90 is longer than the average life of H13 steel. QRO-90 is used in brass and copper extrusion ram and die sets, life expectancy is longer than the average H13 steel. Copper extrusion bushings, QRO-90 lifetime also extend the same lot. 3) forging die: QRO-90 in the continuous forging iron, brass, especially the small and medium sized die life, life performed particularly well. QRO-90 is particularly suitable for continuous forging, forging, extrusion forging, powder forging and require large amounts of water to cool the other forging technology