Transport cylinder and manufacturing method thereof as well as pumping device comprising transport cylinder

Abstract

The invention discloses a transport cylinder and a manufacturing method thereof as well as a pumping device comprising the transport cylinder. The manufacturing of the transport cylinder comprises the steps of: forming a first intermediate cylinder block by machining; carrying out high-frequency induction hardening on the internal surface of the first intermediate cylinder block to form a hardening layer on the internal surface of the first intermediate cylinder block so that a second intermediate cylinder block is formed; and plating a chrome coating on the external surface of the hardening layer to form the transport cylinder. By using the method, the hardness of the surface of the cylinder block is improved by high-frequency induction hardening so that the hardness difference between the surface of the cylinder block and the chrome coating plated thereon is diminished, and the thickness of the plated hard chrome coating is diminished simultaneously, thereby lowering interlayer stress between the cylinder block surface and the chrome coating and the innerstress and friability of the plated coating, in turn, lowering the cracking ratio of the chrome coating on the transport cylinder surface and decreasing the abscission of the hard chrome coating so as to prolong the service life of the transport cylinder. Meanwhile, the high-frequency induction hardening process has high efficiency and low cost, and is beneficial to industrial production and environmental conservation; and by adopting the process, the thickness of the hard chrome coating is decreased, and plating cost islowered.

Description

technical field [0001] The invention relates to the field of concrete construction, in particular to a delivery cylinder, a preparation method thereof and pumping equipment including the same. Background technique [0002] At present, most of the concrete delivery cylinders used in concrete pumping machinery use No. 45 steel as the base of the delivery cylinder, and the inner surface is directly plated with a hard chrome layer with a thickness of 200-300 μm and a hardness greater than HRC64. Layers give the concrete delivery cylinder a long life. [0003] However, the concrete conveying cylinder manufactured by the above process has the following three disadvantages: [0004] 1) Due to the low hardness of No. 45 steel cylinder material, the hardness after quenching and tempering treatment is only HBS260-300, while the hardness of the electroplating layer is as high as HRC64. When the hard particles are pressed on the high-hardness layer, the matrix hardness is too low and i...

AI Technical Summary

Problems solved by technology

[0004] 1) Due to the low hardness of No. 45 steel cylinder material, the hardness after quenching and tempering treatment is only HBS260-300, while the hardness of the electroplating layer is as high as HRC64. When the hard particles are pressed on the high-hardness layer, the matrix hardness is too low and insufficient To support the high-hardness electroplating layer, micro-deformation occurs, resulting in damage to the high-hardness electroplating layer;

[0005] 2) There are many microcracks in the electroplated hard chromium layer itself, and the internal stress is relatively large, which is prone to hard chromium falling off;

[0006] 3) The hardness difference between the high-hardness hard chromium layer and the 45 steel substrate is large, and there must be a large stress on the joint surface, which also causes the hard chromium layer to easily fall off

"Although the delivery cylinder prepared by this method has improved corrosion resistance and bonding force to a certain extent, its milky white chromium hardness is low, generally HRC45-55, and the thickness is only 20-30 microns, which is not enough to support its The outer hard chromium layer with high hardness; at the same time, the thickness of the high hardness hard chromium layer is still relatively thick, reaching 280-300 microns. The thicker the thickness, the greater the internal stress of the layer, resulting in the hard chrome layer still falling off easily