A method of manufacturing the train bands of continuously cast billets

 

(57) Abstract:

The invention relates to a thermal processing train bandages and can be used in the manufacture of products such as bodies of rotation from carbon steel. The objective of the invention is the provision of a more reliable removal of hydrogen from the tyres in the process of their manufacture. The method includes heating the workpieces under deformation, rolling bandages, isothermal their patience, termouprochnenija and leave. What's new is that in the process of heating billets under deformation, after preheating to a temperature of 950oC the surface layers of the workpiece podslushivaet 150-250oC, then heated to a temperature deformation, and after rolling bandages, their slow cooling to a temperature of 300-450oC, followed by isothermal aging at a temperature of 550-650oC, repeat hypothermia tyres up to the same temperature before heating for thermal hardening. 1 Il.

The invention relates to heat treatment of steel.

The main reason for the formation of placenow in bandages is the increased content of hydrogen and steel. The process of removing it from laminated metal consists of two stateradio not below 300oC).

In the diffusion process, which proceeds more rapidly the higher the temperature of the metal.

In this regard, it is rather useful process of cold metal until after deformation, thereby accelerating the release of hydrogen from a solution of its in - gland, and then to heat and can withstand at the maximum temperature, when the diffusion rate it out of metal will be the greatest [1].

A known method of manufacturing products of the type rotating bodies, including podstugivaniya after rolling, heated to a temperature protivogololednoy processing, isothermal aging and slow cooling, then a long gap in time (several days) is heated to a temperature of the heat strengthening, followed by quenching and tempering [2]. This thermal break between isothermal aging and thermal hardening increases the probability of formation of placenow in metal with increased content of hydrogen in steel.

The closest analogue to the technical essence and the achieved result to this object is a method of manufacturing tyres of continuously cast billets, including preheating of the workpieces to 950oC, heating up temperature bandages slowly cooled in an unheated wells, and then on the air, followed by heating to a temperature of the heat strengthening 850oC, rapid cooling your feet in the water tank, a vacation at a temperature of 650oC. In this way the temperature interval the most intense emission of hydrogen from metal 550 - 650oC time is very little and need for cooling in unheated wells. On the other hand, flakey in bandages are formed mainly by cooling them in air below 300oC, which further worsens the conditions protivogololednoy handling car.

The present invention is the provision of conditions for more reliable removal of hydrogen from the tyres in the process of their manufacture.

This task is solved in that in the method of manufacturing the train bands of continuously cast billets, including preheating of the workpieces to 950oC, heating to a temperature of deformation, rolling, isothermal exposure, termouprochnenija and leave, according to the invention after preheating shall podstugivaniya surface layers of the workpiece 150 - 250oC below the preheating temperature and this temperature are heated to a temperature of deformation, the village is Derekoy, then the product preobladayut to 300 - 450oC and this temperature is heated to a temperature of the heat strengthening.

The invention is illustrated in the drawing, which shows the graphs of thermal regimes of splints and bandages in the process of their manufacture by known (solid line) and the new (dashed line) methods. The drawing is taken notation:

For a known way:

1 - heated material in furnaces of up to 950oC,

2 - heat the workpiece in the chamber of the furnace to a temperature deformation;

3 - lowering the temperature of the tyres in the deformation process and set stop;

4 - the temperature decrease during slow cooling in unheated wells and in the air to a temperature of 20oC;

5 - heating of the tyres under termouprochnenija;

6 - cooling of the tires when thermal hardening;

7 - leave of bandages;

for the new method:

1 - heated material in furnaces of up to 950oC;

2 - podstugivaniya surface areas of the workpiece 150 - 250oC;

3 - heat the workpiece to a temperature deformation 1250oC;

4 - reducing the temperature of the tyres in the deformation process and set stop;

5 - cold feet to a temperature of 300 - 450oC;

6 - heating BA C;

8 - heat the tyres up to temperature, heat strengthening 850oC;

9 - cooling bandages in the tank when thermal hardening;

10 - leave the bandages.

The method consists in the following. Source continuously cast billet is heated in furnaces to a temperature of 950oC, after which its surface layers podslushivaet 150 - 250oC. Then, the workpiece is heated to a temperature of deformation in the chamber of the furnace, and after rolling bandages slowly preobladayut to 300 - 450oC and then heated to a temperature of isothermal soaking 550 - 650oC wells, where is isothermal exposure. Then the bandages again preobladayut to 300 - 450oC and this temperature is heated to a temperature of the heat strengthening, cooled in water and carry out the vacation.

Example. In the manufacture of railway tyres with a diameter of 1060 mm concast billet diameter 430 mm, weight 473 kg was heated in furnaces to a temperature of 950oC for 3 hours. Then its surface layers podstegival by fans when Peresada in a chamber furnace at 150 - 250oC followed by heating to a temperature deformation 1250oC. Zagotovka in roughing and finishing mill stands. After marking the bands gathered at the foot of 20 pieces, preobladali to a temperature of 300oC and this temperature was heated to 620oC, which was kept for 3 hours in the ROWLOCK furnaces. Then the foot bandages re preobladali to a temperature of 300oC, warmed up to the temperature of the heat strengthening 850oC, and Thermopanel in the tank with water having a temperature of 35oC within 150 C. Subsequent vacation was produced in the ROWLOCK furnace for 3 hours at a temperature of 580oC. Ultrasonic inspection of 100% made of bandages showed no placenow.

A method of manufacturing the train bands of continuously cast billets, including preheating of the workpieces to 950oC, heating to a temperature of deformation, rolling, isothermal exposure, termouprochnenija and leave, characterized in that after preheating shall podstugivaniya surface layers of the workpiece at 150-250oC below the preheating temperature and this temperature are heated to a temperature of deformation, after rolling the product slowly preobladayut to 300-450oC and heated up to 550-650oC with isothermal exposure, then the product preobladayut to

 

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