Forged 45# Steel Round Forging

Standard No.Alloy No.Chemical compositions(%)CCrMnNiPS SiGB/T699-199945#0.42~0.50≤0.250.50~0.80≤0.25≤0.035≤0.0350.17~0.37MechanicalPropertyTensile Strength(Mpa)Yeild Strength(Mpa)Elongation(%)Contraction of area Z(%)≥600≥355≥16≥40The correlation betweenproperties and parameters-S45C (JIS)-SAE1045(Aisi)-SM45 of No. 45 steel(45 steel) was studied:42CrMO steel belongs to alloy structural steel in terms of ma-terial classification, has good mechanical properties and ma-chinability, and is widely used, mainly has plate and roundbar two types of materials, its comprehensive performance isbetter than 40CR, has been recognized by the industry.No. 45 steel is a carbon structural steel with 0.45% carboncontent. It is characterized by low price, good cutting perfor-mance, high hardness after quenching, good strength, tough-ness and wear resistance after quenching and temperingtreatment, is widely used in manufacturing structural partsand low-grade plastic mold. "45 steel" is a popular name, thesymbol is generally recorded as"45 #". In fact GB standardsteel number is"45", it is not a sequential number, read as"45steel" is not very accurate. Ingredient code 45 steels of similardesignation are S45C (JIS) and 1045(Aisi) . In addition, ourcountry metallurgical technology standard has SM45 brandnumber to express the plastic mold use specially. Comparedwith 45 steel, SM45 has lower phosphorus and sulfur contentand better steel purity.Recommended process specification for heat treatment andhardness: quenching temperature 820 - 860" C, water-oroil-cooled, hardness 250 HRC. Recommended tempering pro-cess specifcation: tempering temperature is 500 - 560" C, aircooling, hardness is 25 - 33HRC. Tempering in this tempera-ture range is the tempering treatment, Quenching and tem-pering make the strength, plasticity and toughness of 45 steelget a good balance, the comprehensive performance is good,can adapt to the alternating load environment. After quench-ing and tempering, the surface hardness of 45 steel is low anddoes not wear well. So commonly used quenching and tem-pering + surface quenching to improve the surface hardnessof parts.  Tempering temperatureAfter quenchingUnit centigrade200300400500550600HardnessHRC57555041332622  StandardsGB/T 699Number45C0.42-0.50Cr