INFORMATIONS ON HARDFACING WELDING What is hardfacing and where is used? Hardfacing is a welding overlay process where a layer of metal of specific pr

Transcription

1 FILLARC Cored wires for hardfacing, overlating, maintenance and repair

2 INFORMATIONS ON HARDFACING WELDING What is hardfacing and where is used? Hardfacing is a welding overlay process where a layer of metal of specific properties are applied on certain areas of metal parts to resist wear and prolong working life. Abrasion, impact, erosion, wear and cavitations are the main causes for material loss. The technology, applied properly, can produce some very satisfying returns and can be used also with corrosive liquids or at high temperatures. Compared to competitive wear prevention treatments the main advantages of the technology are: It is performed by welding, the most economical, easy and commonly used way to join metals permanently, which requires no new or complicated equipment. A layer or layers of metal can be applied. In-depth and long lasting protection is therefore ensured. A wide variety of materials can be applied so as to ensure effective surface protection and meets various application needs. Only a certain area of the metal part that is exposed to wear is hardfaced. There is no need to protect the entire surface of the metal part from wear. Hardfacing can be applied selectively with varying thicknesses so as to meet the requirements needed and provide the most economical way of containing wear. Main hardfacing application Build-up or re-building applications: used to return the metal part to its original dimensions (Fig. 1). Hard surfacing or overlay applications: used to increase the component resistance to wear (Fig. 2). Build-up and overlay applications: build-up and hardfacing can be used together to return the component to its original size and protect the contact surface from additional wear (Fig.3). Some materials can be used as both a build-up and overlay deposit. During service, the final layers can work harder under heavy stress to form a wear resistant overlay. Flux cored wires for hardfacing applications can be used to extend the component life by over twice that of the original component. Additionally, if hardfacing is used as part of a routine maintenance program the original component can be manufactured from a less expensive base material. How to choose the right hardfacing flux cored wire: For a correct hardfacing procedure knowledge of four major factors is required: 1- Type of base material 2- Welding process to be used 3- Type of protection to obtain 4- Buffer layer Build-up Base material Fig.1 Hard surfacing Base material Fig.2 Hard surfacing Build-up Base material Fig.3 1- The component base material should be known in order to decide what type of wire and welding procedure are most suitable. Carbon and low alloy steels and austenitic manganese steels are the most common base metals used Carbon and low alloy steels are strongly magnetic whereas austenitic manganese steels are not. A wide variety of carbon and low alloy steels are used to manufacture metal components. They are not easy to distinguish from one another but must be identified for accurate establishment of pre-heat, interpass, welding wire, cooling rate and stress relief needed. Typically, as alloy content increases base metals become more difficult to weld. As a result, the use of correct pre-heat and interpass temperatures and slow cooling become more crucial.

3 1.2- High manganese (typically 14%) steels are strongly resistant thus they are used to manufacture components subject to both abrasion and extreme impact. Unlike carbon and low alloy steels, manganese steels are rarely pre-heated; in fact base metal temperature during welding must be less than 300 C to avoid embrittlement. 2- At present the most common hardfacing welding procedures are flux cored arc welding (2.1) and submerged arc welding (2.2). Several factors should be considered for a suitable welding procedure/wire combination. -Welding equipment available -Welders skills available -Welding location: indoors or outdoors -Size and shape of the component and area to be hardfaced -Welding position -Flux cored wires available for hardfacing 2.1- Flux cored arc welding is a semiautomatic process that can performed both with and without a shielding gas (open arc). Open arc welding can be done directly on site without having to carry the component indoors for hardfacing. The flux cored arc welding process is becoming increasingly popular for hardfacing applications because of the flexibility in the alloy selection and the higher deposition rates that flux cored wires can provided unlike electrodes and solid wires Submerged arc welding is an automatic process which implies both use of a type of wire (solid or flux cored) and a protective (neutral or additive) flux. Submerged arc welding or hardfacing is far more expensive than flux cored wire arc welding as more complex welding equipment is required. Submerged arc welding is commonly used to hardface large components. 3- For a suitable hardfacing process the type of wear the component is subject to should be known: - metal-to-metal wear: friction between two surfaces that are in intimate contact (Figs 4-5). Fig.4 - impact wear: when subjected to heavy impact and flexion a metal surface is distorted and cracks generating metal particles (Fig. 6). - wear caused by powdery materials: solid particles (grit and so forth) impact on the metal surface (Fig. 7). Fig.6 Fig.7 - pressure wear: caused by the rolling of two pieces one upon the other. - corrosion wear: due to chemicals. - erosion wear: it occurs when a metal part is in intimate contact with a liquid. If the liquid is corrosive a combination of erosion-corrosion wear will occur. With solid particles in suspension instead a combination of erosion-abrasion wear will occur. - cavitations wear: heavy impact of liquid droplets or bubbles on a metal surface. - wear due to heat: vessels or containers lose weight when cooling after exposure to high temperatures. A similar process occurs when a metal part is heated and then cooled into water: flakes of oxide zed metal are formed. 4- A buffer layer is an intermediate deposit applied between the base material and the hardfacing deposit. Hardfacing on a soft material for high load service A hardfacing deposit may sink into the base material if this is soft and loading is high. The application of a strong and tough layer on the base material before hardfacing helps overcome this sinking tendency. Hardfacing on components subject to heavy impact/flexing Relief checks may form when a component (especially very hard hardfacing products) is subject to heavy impact and flexion. These may then act as stress concentrators and spread through the base materials particularly if high strength steels are the base materials used. A buffer layer will provide a suitable solution to this problem. Hardfacing over partly worn components Hardfacing can be applied directly on softer, multilayered deposits and/or deposits that have not fractured. Fractured and very hard deposits should be removed by grinding before being hardfaced again. If grinding is not possible, the existing hardfacing deposit can be secured by applying a buffer layer and thus become a tough base for future hardfacing applications. Fig.5

4 1 MANGANESE STEEL APPLICATIONS: Rails, buffer layers, crusher, cylinders and hammers. 2 BUILD UP APPLICATIONS: Crawler rollers, crawlers, pneumatic cylinderstoothed wheels and chains. 3 LOW ALLOWED STEELS APPLICATIONS: Crane wheels, undercarriage parts, gravel pumps and conveyor chains. 4 STAINLESS STEELS APPLICATIONS: Continuous casting rolls, turbines and valves.

5 5 TOOL STEELS APPLICATIONS: Dragline bucket, hammers, cement rolls, sugarmills and dredges. 6 HIGH METAL CARBIDES APPLICATIONS: Cyratory crushers, chutes and liners, pulveriser tables, wear plates and bucket teeth. 7 NICKEL ALLOY APPLICATIONS: Hammers, hot extrusion dies, extrusion punches. 8 COLBALT ALLOY APPLICATIONS: Valves, valve seat and extrusion screws, tools and valves for chemical industry.

6 1 2 3 Corrosion and Temperature resistance High low low high FILLARC Products DUR 257 M DUR 207 O DUR 351 B DUR 352 B DUR 252 M DUR 405 B DUR 503 B DUR 506 B DUR 551 B DUR 606 B 1 MANGANESE STEELS DUR 404 M DUR 405 M DUR 550 M DUR 554 M DUR 600 M DUR 603 M DUR 606 M DUR 5510 M DUR 405 M AS DUR 5510 O Classifications Abrasive resistance Impact resistance 2 BUILD UP DIN 8555: MSG 7 - GF KP EN 14700: T Fe 9 DIN 8555: MF 7 - GF KP EN 14700: T Fe 9 DIN 8555: MSG P EN 14700: T Fe 1 DIN 8555: MSG P EN 14700: T Fe 1 DIN 8555: MSG 1 - GF P EN 14700: T Fe 1 DIN 8555: MSG 5 - GF P DIN 8555: MSG 3 - GF P DIN 8555: MSG 6 - GF P EN 14700: T Fe 2 DIN 8555: MSG 5 - GF P EN 14700: T Fe 4 DIN 8555: MSG 6 - GF P DIN 8555: MSG 3 - GF ST DIN 8555: MSG 5 - GF P DIN 8555: MSG PT DIN 8555: MSG 3 - GF ST DIN 8555: MSG 6 - GT GP DIN 8555: MSG 3 - GF 60 - GPZ DIN 8555: MSG 6 - GF - 60 GP DIN 8555: MSG 10 - GF P DIN 8555: UP5 - GF - 40 DIN 8555: MF 6 - GF GP 3 LOW ALLOYED STEELS STAINLESS STEELS TOOL STEELS HIGH METAL CARBIDES 7 NICKEL ALLOY 8 COBALT ALLOY high low O = OPEN ARC B = BASIC M = METALCORED AS = SAW C % % Si Mn % Cr % Ni % Mo % Ti % Nb % % V W % Fe % Co % Hardness bal. HB: bal. HB: bal. HB: bal. HB: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: 57-62

7 4 5 6 FILLARC Products DUR 255 M DUR 402 M DUR 403 M DUR 455 M DUR 455 M AS DUR 158 O DUR 504 B DUR 505 B DUR 555 B DUR 556 B DUR 453 M DUR 456 M DUR 503 M DUR 553 M DUR 555 M DUR 6010 M DUR 6011 M DUR 456 M AS DUR 6510 O DUR 6511 O DUR 6512 O 7 INCO DUR C AS 8 STEL DUR 21 AS Classifications DIN 8555: MSG 5 - GF C DIN 8555: MSG 5 - GF C DIN 8555: MSG 5 - GF C DIN 8555: MSG 5 - GF ST DIN 8555: UP5 - GF - 45 DIN 8555: MF - GF - 150/400 KPZ DIN 8555: MSG 3 - GF ST EN 14700: T Fe 4 DIN 8555: MSG 5 - GF CP EN 14700: T Fe 6 DIN 8555: MSG 6 - GF CP EN 14700: T Fe 6 DIN 8555: MSG 6 - GF P EN 14700: T Fe 4 DIN 8555: MSG 3 - GF ST EN 14700: T Fe 3 DIN 8555: MSG 6 - GF G EN 14700: T Fe 6 DIN 8555: MSG 3 - GF ST DIN 8555: MSG 3 - GF ST EN 14700: T Fe 3 DIN 8555: MSG 5 - GF ST DIN 8555: MSG 10 - GF CPG EN 14700: T Fe 14 DIN 8555: MSG 10 - GF G EN 14700: T Fe 13 DIN 8555: UP6 - GF - 45 EN 14700: T Fe 6 DIN 8555: MF 10 - GF G EN 14700: T Fe 16 DIN 8555: MF 10 - GF GT EN 14700: T Fe 16 DIN 8555: MF 10 - GF G EN 14700: T Fe 16 DIN 8555: UP 23-GF-200/350 CKNTZ AWS A5.21: ERCNiCrMo 5A DIN 8555: UP 20-GF-350/50 CKTZ AWS A5.21: ERCCoCr-E C % % Si Mn % Cr % Ni % Mo % Ti % Nb % % V W % Fe % Co % Hardness bal. HB: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HB: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal. HRc: bal HB: bal. HRc: 33 The list of products is not a limiting list. Please do not hesitate to contact us fot other product not in the list.

8 FILLARC FILL ALLOY GROUP LIMITED 电话 : info@fillalloy.com