SU959956A1 - Method of preparing blanks for electric slag welding - Google Patents

Description

(54) METHOD FOR PREPARING PLANTS UNDER ELECTROSHLACK WELDING

one

The invention relates to welding, and more specifically to electroslag welding, and can be used in electroslag welding of mainly cast billets with straight seams.

A known method of preparing blanks for electroslag welding, in which the initial and final technological single-use strips are welded to the blank to bring the final and initial sections of the weld, which have inevitable defects 1, out of the base metal.

However, this method requires a lot of work. The initial and terminal strips must be tightly fitted to the blanks so that there are no gaps into which the slag bath spreads, and then they are welded by manual arc welding. Blanks must be turned over for welding of initial planks and after assembly. When welding, for example, chrome-molybdenum steels in the heat-affected zone of the upper part of the electroslag weld, cracks are formed due to the fact that the upper part of the base material overheats and the edges turn.

There is also known a method of preparing billets for electroslag welding, including the manufacture of exit strips and bottom attachment, while the lead-in bar is made in one piece with the workpiece 2} 5 The disadvantage of this method is that the use of initial strips made in one piece with the workpieces is not provides quality due to the occurrence of cracks in the initial strips, which, Q rye, extend into the base metal. When the slag bath enters the output strips from intensive one-sided heating, the shells are deformed and destroy the seams of manual arc welding, forming gaps between the exit plate and the workpiece, the liquid slag leaks in KOTOIS, and the depth of the slag bath decreases sharply, which leads to violation of electroslag welding conditions and the appearance of defects in the welding seam.

The aim of the invention is to increase

20 weld quality and increased productivity by reducing preparatory operations.

This goal is achieved by the fact that according to the method of preparing blanks for electroslag welding, including the production of leading strips and attaching the bottom, forming a "pocket with lead-in bars, in which the lead bars are made in one piece with the workpiece, and the output bars are made in one piece with the workpiece and the thickness of the slats is determined based on the allowable temperature, according to the formula 2 -TYH where B is the thickness of the slats, see a is the power of the welding process, cal / s; 8 - thickness of the metal being welded, cm; H - the height of the bar, cm; h is the depth of the slag bath, cm; tj is the specific heat capacity of steel, cal T - the temperature of heating of the strips is allowed, ° С; Y - welding speed, cm / s. the drawing shows the implementation of the proposed method. The blanks 1 and 2, the lead-in (initial) strips 3 and the output strips 4 are made in one piece. The bottom 5 forms with the initial strips 3 a pocket fixed, for example, with a screw or a wedge 6. In order to avoid welding the bottom 5 to the pockets and initial strips, a gasket 7 is installed in the welding gap. The method is implemented as follows. The sample is made of ZOL steel with a thickness of 220 mm and installed under electroslag welding with a 30 mm welding gap. The sample blanks are cast in one piece with the initial and leading plates, whose thickness is calculated by the formula R U I-L S SST-TYH for given parameters of electroslag welding Zrc - welding current 50A; U - welding voltage 50 V; P - the number of electrodes 2 pcs .; sy - welding speed 0,0166 cm / s; H - the height of the initial and output strips 10 cm; h - the depth of the slag bath 5 cm; CJ - specific heat capacity of steel ZOL with an average temperature of 300 ° С 1.21 cal / cm deg .; Y - electrode feed rate of 240 m / h - 1.1 cal / cm deg. at a temperature of 400 ° C. q 12 хО, 24УЗ „,

allocated to

about - the amount of heat

slag bath;

P - efficiency of 0.9; ((0.9x0.24x50x200x2 10800 cal / s.

At T 600 ° C

О & ОО iO- 5

° 01b6x- (

at T 800С

05

10,800

7.36sl 2.22 1, and X 800 0,0166 X- (O

B - slat thickness;

Claims (2)

1. Electro slag welding. Ed. B. E. Paton Kiev Mashgiz, 1959, with. 138-139. 2. Electro slag welding. Ed. B. Ye. Paton Kiev, Mashgiz, 1959, p. 282 (prototype). D1 N - 5