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Steels with elevated mechanical characteristics Quenched and tempered steels have a chemical composition that has been…

Steels with elevated mechanical characteristics

Quenched and tempered steels have a chemical composition that has been specifically designed to guarantee the best performance after quenching and tempering heat treatment, consisting of a quenching and a subsequent tempering: this process makes the pieces particularly hard and tough, making them suitable for use in even very severe conditions.

Temperability is the capacity of a steel subjected to rapid cooling (usually in oil or water) to more or less completely transform its structure, even on larger pieces.
The quenching and tempering treatment is generally carried out on pieces during the final stage of finishing, after most of the mechanical processing. In this case the semi-finished raw material can be provided in its natural rolling state or annealed for workability, depending on the type of steel.

Thanks to the technologies available, which are in accordance with the most advanced state-of-the-art, Rodacciai can also offer these products in the quenched and tempered state: the treatment is carried out on the rolled semi-finished product before drawing or peeling, so that the delivered product has in any case the appearance and typical surface characteristics of the cold-finished product.

The complete range of quenched and tempered steels, diversified in terms of chemical composition and therefore temperability, allows both the metallurgic and mechanical needs of all customers to be satisfied.

The heat treatments available for this type of steel – to be checked on a case-by-case basis according to the different qualities – are: rolled natural, workable annealed, isothermal annealed, globular annealed, normalized, and quenched and tempered.

Execution Profile Range (mm) Finish Tolerances
Bars Rolled Round 20÷200 Raw, peeled iron product
Drawn Round
Polished ISA h9-h10-h11
Peeled – rolled Round 20÷100 Polished ISA h9-h10-h11
Ground Round 50÷60 Polished ISA h7-h8-h9-h10-h11
Coils Drawn Round
Polished, phosphated ISA h9-h10-h11

Alaşımsız Islah Çelikleri

Kalite Werkstoff No Açıklama Dosya
KV20 R20Pb Non-alloy steel with very low temperability, temperable only in water and used for simple and small pieces. Often used without the quenching and tempering treatment.
KV30 R30S Non-alloy steel quenchable and temperable in water with higher carbon contents than KV20. Used for simple pieces of limited size.
KV35 R35Pb Non-alloy steel quenchable and temperable in water, higher carbon content than the previous types. Widely used thanks to its slightly higher temperability.
KV40 R40S R40Pb Non-alloy steel quenchable and temperable in water and oil, allows higher mechanical characteristics to be obtained. It is one of the most used steels in Europe.
KV45 R45S R45Pb Non-alloy steel, quenchable and temperable in water and oil. Pieces of a particular size with sufficiently transformed structures can be extracted. It is one of the most used steels in Europe.
KV50 R50Pb Non-alloy steel quenchable and temperable in oil, with high carbon levels, allows pieces with rather high hardness to be obtained. Also suitable for surface tempering.
R55 The high carbon levels of this non-alloy quenched and tempered steel allow high hardness and transformed structures to be obtained even in pieces of considerable size. Often used for surface tempering.

Alaşımlı Islah Çelikleri

Kalite Werkstoff No Açıklama Dosya
RK4 RK4S A low-alloy steel with the addition of chromium only, it is primarily used in bolts for small- and medium-sized pieces.
RKS RKSPb A chromium and manganese alloy steel, no longer present in the unified standards, it is widely used in the quenched and tempered state for pins and hubs of heavy equipment and more generally in the automotive field.
RK0S RK0SPb Alloy steel with chrome and molybdenum and a low carbon content; for this reason it is one of the few quenched and welded steels that can be welded (with some precautions) and it is used in gears and for small- and medium-sized pieces. The presence of molybdenum avoids the phenomenon of fragility by tempering.
RK0 Steel similar to the previous one: the greater carbon content makes welding more difficult, but favors temperability.
RD6 RD6Pb Steel with chromium and molybdenum, used in the production of average-sized pieces. At the quenched and tempered state it has good mechanical characteristics and does not suffer from embrittlement from tempering.
RK1 RK1Pb The most widely used of the quenched and tempered steels. The excellent temperability and the absence of embrittlement fragility make this steel suitable for the production of a variety of pieces, also of medium-large size, with high mechanical characteristics.
50CrMo4 Steel similar to the above, but with a higher carbon content. It is used for the same purposes, when a surface hardness obtained by induction tempering is also necessary.
RB2 RB2Pb A steel widely used in Italy, it is in any case included in the European standards. The addition of nickel in addition to chromium-molybdenum improves the performance of the pieces obtained, especially with regard to resistance to fatigue and vibrations.
34CRNIMO6 This is the steel most commonly used in northern Europe when the addition of nickel is required by the severe use conditions. It has an elevated temperability thanks to the presence of significant levels of nickel and chromium: it is even suitable for the construction of large pieces that, at the quenched and tempered state, have well transformed structures down to the core.
30CRNIMO8 Quenched and tempered steel with high temperability and toughness thanks to the high chromium content. It can be quenched and tempered at high resistance values and offers hardness consistency and uniformity. Generally used for pinions and shafts. Has average machinability on tool machines. Can be nitrided at the quenched and tempered state to increase resistance to wear and the fatigue limit.
46CRB2 46CRB2 Steel with a limited addition of chromium and boron, which provide greater temperability with respect to similar steels with carbon only (C45). It is not unified in any standard, but is used in the automobile industry and in other fields.

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