US3896567A

US3896567A - Dredging bucket having a reinforced edge

Info

Publication number: US3896567A
Application number: US414092A
Authority: US
Inventors: Bernd Kos Leoben; Alois Kubasa
Original assignee: Gebrueder Boehler and Co AG
Current assignee: Gebrueder Boehler and Co AG
Priority date: 1972-11-24
Filing date: 1973-11-08
Publication date: 1975-07-29
Anticipated expiration: 1992-07-29
Also published as: GB1405050A; BR7309195D0; FR2208030A1; IT997627B; DE2348772A1; BE807240A; FR2208030B3; NL7315939A; AT319149B; AU6220473A

Abstract

A reinforced dredging bucket of hardened manganese steel has an edge formed from a plurality of successively alternating, integrally cast first and second regions. The first regions consist of the main bucket metal formed from a composition consisting of 0.5 to 2 % carbon; 6 to 30 % manganese; and up to 3 % silicon, chromium, molybdenum, and vanadium, singly or in combination, the rest being iron and steel impurities. The second regions, which may project beyond the first regions to form teeth, consist of a wear-resistant material formed from 1.2 to 4 % carbon; 15 to 30 % chromium; 0.2 to 10 % manganese; 0.1 to 5 % silicon; up to 10 % nickel; and up to 10 % of elements forming carbides and/or nitrides, the rest being iron and steel impurities.

Description

United States Patent 1191 Leolien et al.

1451 July 29,1975

DREDGING BUCKET HAVING A REINFORCED EDGE lnventors: Bernd Kos Leoben; Alois Kubasa,

Mitterdorf, both of Austria Appl. No.: 414,092

2,132,373 10/1938 Bartholomew 76/101 A X 2,429,800 10/1947 Briggs 75/128 A 2,706,696 4/1955 Payson.... 75/128 A X 2,709,132 5/1955 Giles 75/126 A 3,113,861 12/1963 Norman..... 75/123 N 3,330,651 Younkin 75/123 N Primary Examiner 'Clifford D. Crowder 57 ABSTRACT A reinforced dredging bucket of hardened manganese [30}, Foreign Applicationrpriority D steel hals an edge formed"from afpluralitiy of sugcessive y aternatlng, mtegra y cast irst an secon re- Nov. 24,1972 Austria 10006/72 gions The first regions consist of the main bucket metal formed from a composition consisting of 0.5 to [52] US. Cl 37/141 R, 29/1961, 29/213696; 2 carbon; 6 to 30 manganese; and p to 3 Int Cl Eozf 9/28 823p 3/00 con, chromium, molybdenum, and vanadium, singly or Fie'ld "5 N B 128 A in combination, the rest being iron and steel impuri- 75/126 l 191 377141 ties. The second regions, which may project beyond 141T 4 R the first regions to form teeth, consist of a wear- 76 01 resistant material formed from 1.2 to 4 carbon; 15 to 30 chromium; 0.2 to 10 manganese; 0.1 to 5 silicon; up to 10 nickel; and up to 10 of elements [56] References Cited forming carbides and/or nitrides, the rest being iron UNITED STATES PATENTS and Steel impurities. 1,310,528 7/1919 Hadfield 75/123 N 1,430,782 10/1922 Attenborough et a1 37/141 R 2 Clams, 2 Drawmg Flgures l J l J l 1 DREDGING BUCKET HAVING A REINFORCED EDGE The invention relates to a dredging bucket cast in hard manganese steel with a wear-resistant working edge, such buckets being adapted for use, for example, on a conveyor chain. In this specification, refers to percentage by weight.

As a rule dredging buckets which are made of wearresistant steels (consisting of 0.5 to 2 carbon; 8 to 30 manganese; and up to 3 silicon, chromium, molybdenum and vanadium, singly or in combination, the rest being iron and impurities) are produced by casting in a mold. The wearing edges of dredging buckets are exposed to frictional abrasion. The resulting worn portions are repaired by welding on wearresistant materials. The generally expected working life of a dredging bucket is some 5 years, with to welding repairs in that period for maintaining its functional capacity.

The welding work requires prolonged immobilization of an entire conveyor chain, which is composed as a rule of 120 to 140 dredging buckets. Apart from the considerable cost of the welding metal such as wires, the work itself is time-consuming and expensive. Owing to the nature of the lining alloys that are normally employed, only a replacement layer of the same kind, or in the case of hard alloys just one or a few layers, can be produced in most cases. In addition, this necessitates holding welding experts in readiness right at the working site, in order to carry out the necessary repairs then and there.

Proposals for reducing the conveyor laydown times to an economically acceptable minimum have been directed at exchanging complete buckets, and doing the welding work at one time on those that are in most need of repair. This again has occasioned increased costs of transportation and has required very great capital outlay, since in practice almost every conveyor chain with to 30 dredging buckets requires spare buckets, so that the production time saved and the gain thus obtained counterbalanced each other.

The present invention is described below, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a view in elevation of an experimental man- Three. small steel anti-wear plates ll (FIG. 1) whose composition was 2.6 carbonand 5 manganese were then placed by casting in one edge of an experimental plate I of manganese steel whose composition was 1.2 carbon, 12 manganese, and 1% silicon, and this edge was exposed to wear. The cast-in antiwear plates II project about 10 mm from the edge of the hard manganese steel plate I, and are spaced 35 mm apart. The test plate was driven at a peripheral speed of 3 in per second through a bed of abrasive. Quartz sand interspered with basalt splinters was used as the abrasive. The initial duration of the test was four weeks. Visual inspection revealed that the anti-wear plates experienced practically no wear during this period, while the zones between the anti-wear plates exhibited slight erosion. This erosion is shown by hatchings V in FIG. 1.

A subsequent test period of 6 weeks under the same test conditions surprisingly revealed that the parts between the anti-wear plates suffered no further erosion. The anti-wear plates themselves displayed only minor effects of wear and preserved a smooth polished condition.

A dredging bucket in accordance with the invention is shown in section in FIG. 2. The anti-wear teeth are cast into the edge zone VI which is subject to wear.

PREFERRED EMBODIMENT OF THE INVENTION The invention provides a dredging bucket cast in hard manganese steel consisting of 0.5 to 2% carbon, 6 to 30 manganese, up to 3 silicon, chromium, molybdenum, and vanadium, the rest iron and impurities,

the invention consisting in that cast into the wearing edge of the dredging bucket are teeth of a material resistant to wear. The teeth employed here may consist of a wear-resisting steel consisting of 1.2 to 4 carbon, 15 to 30 chromium, 0.2 to 10 maganese, 0.1 to 5 silicon, up to 10 nickel, and up to 10 of elements forming carbides and nitrides, such as tungsten, molybdenum, vanadium, tantalum, niobium, and titanium, joinly or separately, the rest being iron and impurities.

The spacing of theteeth may be between 5 and 150 mm according to the type of stress encountered in service. It must, however, be borne in mind that if the spacing is too wide the erosion may become so deep ganese steel plate one edge of which is provided with v wear resistant teeth; and

FIG. 2 is a fragmentary side elevation of a dredging bucket, parly in section.

EXPERIMENTATION Extensive experiments testing various types of steel for wear have shown that a steel containing 2.6 carbon, 25 chromium, and 5% manganese, the rest being iron and impurities normally found in steel, is ten times more resistant to wear than a steel with 1.2 carbon, l2 manganese, and 1.5 chromium, the rest being iron and impurities. Unfortunately, however, casting tests have revealed that the first-mentioned type of steel is technically unsuitable for producing dredging buckets.

A further attempt at mounting small cast'pieces of this wear-resistant quality upon the base body by means of a mechanical bond had to be abandoned, because the joint would not stand up under the working stresses encountered.

that the teeth lose their hold in the body of the bucket and fall out. As the wear experiment described above shows the most advantageous spacing a (FIG. 1) be-' I tween two teeth is fromv 30 to 60 mm in practice.

Further experiments have shown that the wear resistance of the dredging buckets does not decrease if the teeth do not project from the working edge.

Although the invention is illustrated and described with reference to a plurality of preferred embodiments thereof, it is to be expressly understood that it is in no way limited to the disclosure of such a plurality of preferred embodiments, but is capable of numerous modifications within the scope of the appended claims.

What is claimed is:

1. As an improved article of manufacture, a reinforced dredging bucket of hard manganese steel, the bucket having an edge formed from a plurality of successively alternating, integrally cast first and second regions, each first region consisting by weight of 0.5 2 carbon, 6 30 manganese, up to 3 of at least one element selected from the group consisting of silicon, chromium, molybdenum, and vanadium, the remainder' being iron and steel impurities, each second region consisting by weight of 1.2 4 carbon, 15 30 chromium, 0.2 to 10 manganese, 0.1 5 silicon, up to nickel, up to 10 of at least one car 5 bide-forming or nitride-forming element selected from the group consisting of tungsten, molybdenum, vanafirst regions to define teeth on the edge of the bucket.

Claims

1. AS AN IMPROVED ARTICLE OF MANUFACTURE, A REINFORCED DREDGING BUCKET OF HARD MANGANESE STEEL, THE BUCKET HAVING AN EDGE FORMED FROM A PLURALITY OF SUCCESSIVELY ALTERNATING, INTEGRALLY CAST FIRST AND SECOND REGIONS, EACH FIRST REGION CONSISTING BY WEIGHT OF 0.5-2% CARBON, 6-30% MANGANESE, UP TO 3% OF AT LEAST ONE ELEMENT SELECTED FROM THE GROUP CONSISTING OF SILICON, CHROMIUM, MOLYBDENUM, AND VANADIUM, THE REMAINDER BEING IRON AND STEEL IMPURITIES, EACH SECOND REGION CONSISTINGBY WEIGHT OF 1.2-4% CARBON, 15-30% CHROMIUM, 0.2 TO 10% MANGANESE, 0.1-5% SILICON, UP TO 10% NICKEL, UP TO 10% OF AT LEAST ONE CARBIDE-FORMING OR NITRIDE-FORMING ELEMENT SELECTED FROM THE GROUP CONSISTING OF TUNGSTEN, MOLYBDENUM, VANADIUM, TANTALUM, NIOBIUM, AND TITANIUM, THE REMAINDER BEING IRON AND STEEL IMPURITIES.

2. The improved article as defined in claim 1, in which the second regions extend outwardly beyond the first regions to define teeth on the edge of the bucket.