(Based on patent of Russia # 2017838) - 39 Kb (*.jpg)
|Broad Area of Technology:||Materials Science and Engineering, Composite Materials|
|Narrow Field:||Heat Treatment of Metals and Alloys|
|Purpose:||The process permits increasing the mechanical properties, performance and service characteristics of structural and tool steels|
Brief Description and Specific Features
The process implies the usage of conventional equipment for heat treatment and does not require additional hardware. A new regime of hardening and tempering (the time-temperature schedule, sequence of operations and the chemical composition of the cooling medium constitute the "know-how") permits obtaining fine-grained microstructure of structural and tool steels. In comparison with the conventional heat treatment regimes, this treatment increases the tensile strength by 10 - 50%, plasticity by the factor of more than 2 and the impact strength by the factor of 2 - 15 retaining high hardness of the hardened steels.
Advantages Over Standard Heat Treatment
Structure and Properties of Processed Steels
The use of the developed heat treatment process, which increases the duration of the operation by only 10 - 20%, permits obtaining on certain brands of steels the properties close to those of the damask steel. For example, for the unalloyed steel Y8 (0.8% C) with the hardness of HRC 59 - 60 after the treatment, the impact strength of unnotched samples sized 10x10x55 mm was increased by the factor of 13 - 15: from 0.2 MJ/m2 (after standard heat treatment) up to 2.5 - 3 MJ/m2; the bending strength of samples sized 5x10x55 mm was improved by 25 - 35%: from 2850 MPa to 3550 - 3850 MPa. The microstructure of the processed steel consists of a uniform mixture of high-carbon and low-carbon martensite. "Soft" low-carbon martensite imparts high plasticity and impact strength to the Ó8 steel while "hard" high-carbon martensite gives high strength and hardness; this structure-property relationship in a carbon steel is similar to that in the damask steel.
The process was tested on structural and tool steels produced in ex-USSR in industrial conditions on several enterprises in Belarus and Russia.
Examples: the improvement of properties of processed tools and articles
|Screw taps||Y8 (0.8% C)||service life||2|
|Threading dies||9XC (0.9% C, 1% Cr, 1.5% Si)||service life||2|
|Top dies, punches die steel||X12 (2% C, 12% Cr)||service life||2|
|Bullets, projectiles||-||penetrability||> 2|
The process is easy to implement, ecologically safe, uses standard hardware for heat treatment and can easily be automatized.
Possible Ways of Cooperation
(1) The process is available "as is". Additional tests may be required for brands of steels not available in Belarus.
(2) This technology gives an opportunity for the development of novel steels possessing a combination of high tensile and impact strength, new special steels, steels with shape-memory effect, wear-resistant steels on the basis of modern technologies. For this purpose, additional investments for carrying out joint researches with a foreign partner are required.
For more information please contact the author:
Belarussia State Polytechnic Academy
65 F.Skorina Ave., built. 7
Phone: (375) 17 2581066 (home), 2399260 (office)
Fax: (275) 17 2329137
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