JPS6056199A - Pump - Google Patents

Abstract

PURPOSE:To prevent seizure between spindle and impeller by performing build- up welding of austenite stainless steel onto the contact face with the spindle of impeller then further applying build-up welding of aluminum bronze. CONSTITUTION:A steel impeller 2 is mounted on the spindle made of 13Cr steel. At first, austenite stainless steel is build-up welded onto the contact face with the spindle 1 and the impeller boss section 2' then aluminum bronze is further build-up welded. Consequently, seizure between the spindle 1 and impeller 2 can be prevented to facilitate welding of easy-to-scratch aluminum bronze.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pump that prevents seizure of the contact portion of a roller.

In the pump, in consideration of mechanical strength and corrosion resistance, 130r is used as the material for the main shaft 1 and invera 2 shown in Fig. 1.
Steel (forged steel or cast steel) is used. While the pump is in use,
Although repeated disassembly and inspection will be carried out, it is necessary to remove the inverter 2 from the main shaft 1 during disassembly. Since the impeller 2 is shrink-fitted to the main shaft 1 in a bracket that is fixed to the main shaft 1, when removing the impeller 2, the impeller 2 is heated with a burner and pulled out from the main shaft 1 with a hydraulic jack. However, the main shaft 1 and the impeller 2 must be of the same quality, so the main shaft 1 and the impeller 2 must be the same. Burn-in may occur on the contact surface. In addition,
The locations where burn-in occurs are shown in FIG. In FIG. 1, reference numerals 3 indicate the casing, arrow a indicates the direction in which the impeller is pulled out, and arrow b indicates the direction in which the casing is pulled out.

If the above-mentioned seizure occurs, the expensive main shaft and impeller must be discarded, which poses an economic problem.

In order to prevent this scrapping, it is necessary to eliminate seizing of the main shaft and impeller.

The inventor of the present invention has made the following findings as a result of intensive research to eliminate burn-in. Obtained.

In order to prevent the main shaft and the inveler from seizing and cracking, it is thought that it would be good to use a soft moon phase on one of the contact surfaces of the main shaft or the inveter. However, from the viewpoint of mechanical strength and corrosion resistance, 150r steel is required for both the main shaft and impeller. Therefore, a method of overlaying a soft material on the 130r steel can be considered. Copper alloys are good for this soft material because of their corrosion resistance. As a build-up method, welding is still better in terms of kL adhesive strength. Aluminum bronze is the most suitable material that satisfies these points. By the way, since the overlay is made of soft aluminum bronze, it is necessary to weld and repair the aluminum bronze when inspecting or disassembling the pump.

However, aluminum bronze on 13Cr steel (e.g.
When welding and repairing a 150r steel heat-affected zone (approximately Hv 45[
J~500)j, Delayed destruction occurs during use. Therefore, instead of directly overlaying aluminum bronze on 130r steel, we first overlay austenitic stainless steel and
r The portion of the steel that will become the heat-affected zone is softened in advance by annealing, and then aluminum bronze is overlaid.

By doing so, it becomes possible to repeatedly inspect and repair scratches on the aluminum bronze during use and disassembly by welding. In other words, the thermal effect of welding repair of aluminum bronze only affects austenitic stainless steel, and 150R steel is hardened and delayed fracture can be prevented. For some reason:, 1! Since +Or steel is a material with a Me point above 0°C, welding directly to 130r steel1. However, austenitic stainless steel does not harden by welding because its Me point is below 0°C. Therefore, if the hardened part of the 130R steel is softened by overlaying the austenitic stainless steel, then annealing and annealing it, welding of aluminum bronze on the austenitic stainless steel (including repair welding) is possible. This eliminates the need for annealing, making repair welding easier and preventing seizure.

The present invention was made based on the above findings, and 130
r In a pump having a steel main shaft and an impeller manufactured by 1.1, the contact surface of the impeller with the main shaft is first overlaid with austenitic stainless steel, and then aluminum Wfjl is overlaid on the contact surface of the impeller with the main shaft. This article relates to a characteristic pump.

In the present invention, the reason why the impeller is overlaid with austenitic stainless steel and aluminum bronze is because the impeller is a cast 150r steel product, and the main shaft is a forged 130r steel product. This is because it cannot be welded.

In addition, in the present invention, if the overlay thickness of the austenitic stainless steel is too thin, the base material (i.e. impeller) will harden due to the heat effect during the overlay of the aluminum bronze overlaid on the austenitic stainless steel. If it is too thick, there is a problem with the material (i.e., austenitic stainless steel is a different material from the base material 130R steel, and the presence of a large number of regions with different materials is a problem).
It is desirable to set it to about 2 to 6 centimeters.

It is technically difficult to build up a thin layer of aluminum bronze on top of the austopite stainless steel, and if it is too thick, strength problems will occur. Therefore, it is desirable to set it to about 0.5 to 6 hours.

FIG. 2 is a diagram showing an example of an embodiment of the present invention.

In Figure 2, one 150r steel main shaft, 2 is 15
(!r @ impeller, the main shaft 1 of the impeller 2
(lql in Figure 2, impeller 2')
The contact surface with the main shaft 1 is first made of austenitic stainless steel, and then aluminum bronze is overlaid thereon.

According to the present invention described in detail above, it is possible to prevent seizure between the main IVII 1 and the impeller 2, and to easily perform welding repair of aluminum bronze, which is prone to scratches.

The present invention is applicable to pumps that have a 1scrm4 main shaft and impeller and are inspected and disassembled repeatedly, such as condensate pumps, condensate boosters, and water booster pumps that can be used in thermal and nuclear power plants.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing the structure of the main shaft and impeller of an ordinary pump, and FIG. 2 is a diagram showing an embodiment of the present invention. Sub-Agent 1) Meifu Agent Ryo Hagiwara - Figure 1 Figure 2

Claims (1)

[Claims] A pump having a main shaft made of 150r tM and an impeller made of the same steel, characterized in that the contact surface of the impeller with the main shaft is first overlaid with austenitic stainless steel, and then aluminum is overlayed on top of that. pump.