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NEW BRAZE FILLER MATERIALS AND BRAZE TECHNIQUES FOR JOINING FERRITIC AND AUSTENITIC STEELS AND SUPERALLOYS WITH BETTER MECHANICAL AND CORROSION PROPERTIES

Objective


This project succeeded in developing a new brace technique for nickel alloys. By means of a pack-cementation process, nickel allows were converted into a braze material by coating them with boron, silicon, or boron plus silicon (B, Si, or B+Si), all melting point depressing elements.
THE CONTRACT AIM IS TO IMPROVE THE EFFICIENCY OF NICKEL-BASED FILLER METALS ACCORDING TO FOUR SPECIFIC OBJECTIVES:

A. CHARACTERIZATION OF THE BEHAVIOUR OF THE DIFFERENT FAMILIES OF FILLER MATERIALS (NI-B, NI-SI, NI-P AND NI-B-SI) ESPECIALLY WITH RESPECT TO CR AND OTHER ALLOYING ELEMENTS (E.G. FE) IN TERMS OF MICRO-STRUCTURAL COMPOSITION, MELTING, WETTING AND FLOW BEHAVIOUR AND OF BRAZED JOINTS FORMED WITH A FEW SELECTED WORKPIECE MATERIALS IN TERMS OF CHEMICAL AND MECHANICAL INTEGRITY. DTA, SEM AND EPMA TECHNIQUES ARE TO BE EMPLOYED TO QUANTIFY AND QUALIFY CHARACTERISTICS OF FILLER METALS AND BRAZED JOINTS.

B. DEVELOPMENT OF A NEW BRAZING TECHNIQUE, WHERE THE BRAZE IS PRODUCED AT THE SURFACE BEFORE JOINING BY ALLOYING WITH MELTING POINT DECREASING ELEMENTS LIKE BORON AND SILICON.

C. CODIFICATION OF THE COMPOSITIONS, BRAZING PROCEDURES AND JOINT DESIGNS FOR THE OPTIMUM USE OF NICKEL-BASED FILLER METALS, AND FOR THE FIRST TIME GUIDELINES FOR THE CREATION OF NEW BRAZED JOINTS, WHICH ARE CORROSION RESISTANT IN AQUEOUS SOLUTIONS CONTAINING CL IONS, 1 TO 3 % OF DILUTED NITRIC ACID HNO3, AND SERVICE ENVIRONMENTS EXHIBITING TEMPERATURES UP TO 800 CELSIUS DEGREES AND DYNAMIC STRESS (UP TO 10 TO THE POWER 7 CYCLES).

D. ACHIEVEMENT OF ECONOMICS THROUGH THE DEVELOPMENT OF LOWER TEMPERATURE MELTING BRAZING METALS. A DECREASE BETWEEN 75 AND 100 CELSIUS DEGREES WITH RESPECT TO COMMERCIALLY AVAILABLE FILLER METALS IS EXPECTED.

BETTER JOINT CHARACTERISTICS FOR USE WITH BOTH ADVANCED AND CONVENTIONAL MATERIALS IN PRODUCTION ARE TO INCREASE THE RELIABILITY OF THE PRODUCTION PROCESS AND DECREASE THE AMOUNT OF SUBSTANDARD ARTICLES.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Elbar BV
Address

5943 AD Lomm
Netherlands

Participants (3)

AACHEN UNIVERSITY OF TECHNOLOGY
Germany
Address
Templergraben 55
52056 Aachen
Pasilac Flow Equipment A/S
Denmark
Address

8700 Horsens
RISOE NATIONAL LABORATORY
Denmark
Address
Frederiksborgvej 399
Roskilde