SU1675102A2 - Method of manufacture of hydraulically pressed pipes - Google Patents

Abstract

The invention relates to the manufacture of precast concrete and reinforced concrete products and reduces the consumption of metal. This is achieved by calibrating the steel shell with an internal hydraulic pressure of 2.0-3.2 MPa wound to it in the method of manufacturing hydropressed pressure pipes before feeding the concrete mix.

Description

The invention relates to the manufacture of precast concrete and reinforced concrete products and is an improvement of the invention according to the author. St. No. 1308500.

The purpose of the invention is to reduce metal consumption.

The method of manufacturing hydraulic pressurized tubes is carried out as follows.

In the welding mill, steel tape with a thickness of 1.0-2 mm is rolled into a spiral pipe with welding of seams. Spiral-welded pipes cut into lengths and measure the previously manufactured sleeve and socket elements. The assembled steel cylinder is preliminarily checked for tightness of the welds using known methods. A variant of seams with known methods is possible, including the option of testing with an internal hydraulic pressure of up to about 1.5 MPa with the subsequent elimination of detected defects. Then spiral reinforcement armature is wound onto the cylinder with a design step, fastened its ends to

sleeve and flare shell. As spiral reinforcement can be used reinforcement classes BP-1, VRP-1, VRK-1, etc.

After winding the spiral reinforcement, the steel cylinder is calibrated with an internal hydraulic pressure of 2.0-3.2 MPa, which is fixed by two manometers installed on the test bench and communicating with the water in the pipe.

The finished cylinder is installed on the core and the inner lining of the steel cylinder is formed by feeding concrete mixture into the annular space between the steel cylinder and the core under vibration and radial pressing followed by heat treatment. Then, the outer facing is molded by filling the concrete space of the annular space between the steel cylinder and the external formwork under vibration and again heat treatment is performed, after which it is dismantled.

cl

with

about vi ate

about

go

Yu

Example. Make a pipe with a steel cylinder with a nominal diameter of 530 mm. Prefabricated socket and sleeve are welded under a flux layer to a 1.5 m thick steel cylinder, which is then tested at the hydraulic stand for the density of welds and base metal with a pressure that provides stress in the metal up to 1.4 MPa. Then, with a tension of 20 kg, spiral reinforcement of class BP-1 with a diameter of 5 mm with a step of 6 mm is wound on a steel cylinder.

After that, the steel cylinder is calibrated with an internal hydraulic pressure of 2.0 MPe. The finished cylinder is installed with the bell socket down on the core with a rubber boot, it is centered with wedges with vibrators and the vibrocone is installed. The manufacture of the pipe is made of a concrete mixture C: P: B 1: 2.5: 0.4 by weight by successively molding the inner and outer linings.

First, the inner lining is formed by filling the annular space between the steel cylinder and the core under vibration, removing the vibrating cone and centering wedges,

set the locking ring, carry out the hydraulic pressing pressure of 2.7 MPa and within 20 minutes and heat treatment. Then the outer facing is formed, for which an external formwork is installed, a wedge and a vibrating bar are centered, and a concrete mix is supplied to the annular space between the external formwork and the steel shell, followed by heat treatment of the external facing.

Another example of pipe manufacturing is carried out similarly to the first one and is characterized in that the calibration of the steel cylinder is carried out with a hydraulic pressure of 3.2 MPa, and when the inner lining is molded by hydraulic pressing it is carried out with a pressure of 2.9 MPa for 30 minutes.

Claims (1)

The invention The method of manufacturing hydraulic pressurized pipes according to the author. St. No. 1308500, characterized in that, in order to reduce the metal consumption, before feeding the concrete mixture, the steel shell is calibrated with reinforcement wound on it with an internal hydraulic pressure of 2.0-3.2 MPa.