SU1488327A1 - Method of restoring steel articles - Google Patents

Description

The invention relates to thermomechanical processing and can be

The invention relates to the field of thermomechanical treatment when restoring the crankshafts of automotive engines.

The purpose of the invention is the improvement of operational properties.

Example. Carried out technical processing of steel crankshaft. After the traditional methods of preparation for the restoration, the shaft was subjected to a five-fold thermal cycling in the temperature range of 750-650 C in order to crush the structure on the shaft surface and reduce thermal stresses during the subsequent surfacing. At 600 ° C, electric arc surfacing with wire 1.2 Sv 18HGS was carried out under the flux layer AN-348A. In the future, the deposited layer is subjected to

used in the restoration of crankshafts of automotive engines. The purpose of the invention is to improve the performance properties of parts.

To do this, the restored parts are subjected to five-fold thermal cycling treatment in the temperature range of 750-650 ° C, welding is performed on the restored sections, and then three-fold thermal cycling processing is performed with heating to 750-770 ° C and cooling to 650 -. · 500 ° C '. Moreover, in each cycle during cooling, the part undergoes plastic deformation with the degree of G, 02.0%, and after the last cycle with a

temperatures of 750-770 ° C are zakdlka and vacation, 2 Cp f-crystals, 1 tab.

It was heated to triple cycling with heating to 750 ° С and cooling in air to 500 ° С (below Ar). In each cycle, in the temperature range of 750–500 ° C, surface plastic deformation was carried out, with a degree of 1,5 1.5% deformation using the neck rolling method with a pressure of 1200 N and in order to accelerate the formation of a fine-grained structure, increase the dislocation density, reduce the amount of thermal cycling, decrease height the roughness of the deposited layer, reducing metal loss during final machining.

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After the last heating cycle with

750 ° C was hardened in oil and tempering at 150 ° C.

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Samples cut from the crankshaft, reconstructed by the proposed and known methods, were subjected to fatigue strength testing. The test results are shown in the table.

As these tables show, the recovery of the proposed method increases the hardness, toughness and fatigue strength of the metal "

Claims (1)

Claim 1. The method of restoring steel parts, mainly crankshafts, including surfacing, thermal cycling, plastic deformation and · final machining, distinguishing4 With the fact that, in order to improve operational properties, before surfacing, thermocycling is carried out in the temperature range of 75 ° -65 ° C, after heating, thermal cycling is carried out with heating to 75 ° -77 ° C and cooled to 650-500 ° C, and after the last heating cooling in oil and tempering at 100-150 ° С. 2. The way pop. 1, I distinguish y and i with the fact that in each cycle 'after surfacing, the part is subjected to cooling in the temperature range 15 750-500 ° С to surface plastic deformation with a degree of deformation of 1-255, 3, Method of pop, 1, o tl and h a y · y and i with the fact that before the fuse 20 conduct 5-fold thermocycling, and after surfacing 3-fold, A way! processing Heating temperature at thermal cycling after surfacing! —T— · ———— Temperature during cooling during thermal cycling, ° С · (* --------- · - amount cycles TCO Power deformations . 2. ' . ·  . 1 Fatigue strength of the surface layer, kgf * m / cm ² Hardness us Impact strength and ηι «" cm ^and Famous By offering 870 650 , 7 '· 50 45.0 49 3 my 850 670 ten 0.2 43.5 48 6 830 650 eight 0.5: , 47.1 ' 48 6 800 600 6 0.75 4.9,6 50 eight 780 570 .five • '1.0 54.2 51 .ten 750 550 . 3 . · 1.25 56,8 51 eleven 750 550 3 ' 1.50 59.4 52 14 720 500 five . 1.75 , 57.5 50 14 700 · 500 eight 2.0 56,4 48 14 <Λι * п-ι · ι п- · * »п. Ж ..... _. . . . ............ · .. . ______ · ____________________.__ ь! ”- _{- -} l _- m _- 4, "" e, u _{- m} "th _n -----