Product Introduction
The product covered here is a dragging device which is installed in the derrick, and support the mine hoist, hoist support drag between the rolls to enhance the container, and guide the use of wire rope steering. Rope groove is with plastic lining or plastic block, which will increase the service life of wire rope.
Material
This material is the casting steel G42CrMo4 ISO14737:2003(E), which is a fully killed steel, vacuum-degassed and processed to a fine grain size structure with improved properties both in toughness and in elongation.
Chemical composition: (%)
| Elements | C | Si | Mn | P | S | Cr | Mo | Ni | V | Cu |
| Required | 0.38-0.45 | ≤0.6 | 0.6-1 | 0.025 | 0.02 | 0.8-1.2 | 0.15-0.25 | ≤0.4 | ≤0.05 | ≤0.3 |
Mechanical properties
Checked at room temperature in the delivery condition i.e. after completion of the quality heat treatment from cylindrical cast-on test blocks (? 60 mm x 250 mm) available on every Sheaves: both the sample preparation and the testing comply with ASTM A 370-96.
| Properties | Yield strength | Tensile strength | Elongation | Impact Value |
| Required | ≥650 | ≥790 | ≥10 | 27 |
Delivery condition: Hardening and tempering.
Manufacturing
All operations are carried-out at the in-house foundry plant.
Molding
The castings are manufactured in a workman-like manner as required in the German standard DIN EN
1599-1: August 1997, ruling the delivery conditions of castings. The molding is individually carried out within a modular flask by using a sand preparation based on resin bonding.
Melting
The melting is carried out in the oxygen steel plant ( 2 off 180 t BOF converters ); the ladle capacity allows a continuous bottom pouring process the speed of which is permanently controlled. The metal analysis is checked by using a computer linked spectrograph.
Heat treatment
Every sheave undergoes a combined quality heat treatment (Hardening and tempering) aiming both to grain refining and to stress relieving.
Rough machining
In order to meet the inside quality free of defect, we rough machine each sheave foe inner NDT control.
NDT testing
UT: ASTM A609 Level II for the groove and boss center.
MT: 100% ASTM A125 level I
Fine machining
Fine machine every sheave totally according to drawings.
Fettling and dressing
The castings are coated by antirust oil FPC-600 for transportation.
Delivery
Every sheave is packed well and ready for delivery.
Quality assurance
The fabrication route is governed by the provisions of the implemented Quality System ISO 9001: 2000.
The standard documentation ensures the full traceability of every process step:
1. Manufacturer test certificates according to DIN EN 10.204 § 3.1 including chemical composition, mechanical properties and non-destructive examination;
2. Dimensional check supported with a "as-built" sketch;
3. Record of the quality heat treatment
China Special Metal Group Limited (CSM), a supplier of metal material & machinery products, devotes to offer high quality of castings, high-precision machining products, welded fabrications and forgings to valued customers from all over the world. Meanwhile, we offer the design engineering and turnkey project as well.
Our group owns four mainly manufacturing bases. Casting bases in Xinxiang and Yiyang; The welding fabrication base in Wuxi; Special alloy base in Xi'an. Our Shanghai base is the commercial and engineering center. We have our own ISO 9001 certificate.
We have 2 sets of 30 Ton alkaline electric arc furnace; 8sets of transferring ladle with capacity of 35ton, 50tons, and 75tons; 2 sets of baked charter; 4 sets of large heat treatment furnace and the supporting facilities including oxygen generation station, air compression plant, natural gas station, CO station and 22 sets of lifting equipment machines. The lifting capacity reaches 200tons. We own 5 sets of large-scale molding equipment. Meanwhile, we also have the GS1000 vacuum direct reading spectrometer made by OBLF and other inspection equipments like carbon sulfide high-speed analyzer, microcomputer three elements of high-speed analyzer, digital ultrasonic flaw detector, multipurpose magnetic powder flaw detector such as chemical equipment, except that we also own leveraged universal strength tester, SAC thumping machine. Simulating the casting process by the CAE software to ensures the new quality level castings. All the castings are process by arc gouging, carbon dioxide gas gouging, shot-blasted in order to get the surface quality.
Our products include Metallurgical equipment, Cement & Mining machinery. The castings singe weight is up to 120MT. The main products are casting ladles, slag pot, ingot moulds, mill housings, chucks, girth gear & wheel for cement and mining machinery, grinding table and grinding roller for mills, case and covers for pumps, body and beams for all kinds of machine.
