HLQ
Induction heating systems are value added systems that can fit directly into the manufacturing cell, reducing scrap, waste, and without the need for torches. The systems can be configured for manual control, semi-automated, and all the way up to fully automated systems. HLQ induction brazing and soldering systems repeatedly provide clean, leak-free joints for a wide range of parts including fuel lines, heat exchangers, gas distributors, manifolds, carbide tooling, and more.
Principles of Induction Brazing & Soldering
Brazing and soldering are processes of joining similar or dissimilar materials using a compatible a filler material. Filler metals include lead, tin, copper, silver, nickel and their alloys. Only the alloy melts and solidifies during these processes to join the work piece base materials. The filler metal is pulled into the joint by capillary action. Soldering processes are conducted below 840°F (450°C) while brazing applications are conducted at temperatures above 840°F (450°C) up to 2100°F (1150°C).
The success of these processes depends upon the assembly’s design, clearance between the surfaces to be joined, cleanliness, process control and the correct selection of equipment needed to perform a repeatable process.
Cleanliness is ordinarily obtained by introducing a flux which covers and dissolves dirt or oxides displacing them from the braze joint.
Induction Brazing Filler Materials
Induction Brazing filler metals can come in a variety of forms, shapes, sizes and alloys depending on their intended use. Ribbon, preformed rings, paste, wire and preformed washers are just a few of the shapes and forms alloys that can be found.
The decision to use a particular alloy and/or shape is largely dependent on the parent materials to be joined, placement during processing and the service environment for which the final product is intended.
Many operations are now conducted in a controlled atmosphere with a blanket of inert gas or combination of inert / active gasses to shield the operation and eliminate the need for a flux. These methods have been proven on a wide variety of material and part configurations replacing or complimenting atmosphere furnace technology with a just in time - single piece flow process.
Clearance Affects Strength
Clearance between the faying surfaces to be joined determines the amount of braze alloy, capillary action / penetration of the alloy and subsequently the strength of the finished joint. The best fit up condition for conventional silver brazing applications are 0.002 inches (0.050 mm) to 0.005 inches (0.127 mm) total clearance. Aluminum is typically 0.004 inches (0.102 mm) to 0.006 inches (0.153 mm). Larger clearances up to 0.015 inches (0.380 mm) usually lack sufficient capillary action for a successful braze.
Brazing with copper (above 1650°F / 900°C) requires the joint tolerance kept to an absolute minimum and in some cases press fit at ambient temperatures to assure minimum joint tolerances while at the brazing temperature.
Induction heating has proven to be a valuable aid in the joining process for many reasons. Rapid heading and precise heat control offers the possibility of localized heating of high strength components without significantly changing the material properties. It also allows for the brazing of difficult materials such as aluminum and sequential, multi-alloy brazing and soldering of close proximity joints.
Induction heating in brazing and soldering applications is readily adaptable to production line methods, permitting strategic arrangement of the equipment in an assembly line, and if necessary, heating by remote control. Frequently, induction brazing and soldering permits a reduction in the require number of part fixtures, with the minimal heating of the fixtures increasing life span and maintaining accuracy in alignment of the components to be joined. Since operators need not guide the induction heating source, both hands are left free to prepare assemblies for joining.
HLQ
induction brazing equipment delivers quality, consistency, configurable throughput, and quick change-over tooling for various production needs. The Radyne induction brazing and soldering product line offers standard solutions for brazing:
Aluminum
Copper
Brass
Stainless steel
Carbide
And more…
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Induction Brazing Basics for jointing copper,silver,brazing,steel and stainless steel,etc.
Induction Brazing uses heat and filler metal to join metals. Once melted, the filler flows between close-fitting base metals (the pieces being joined) by capillary action. The molten filler interacts with a thin layer of the base metal to form a strong, leak-proof joint. Different heat sources can be used for brazing: induction and resistance heaters, ovens, furnaces, torches, etc. There are three common brazing methods: capillary, notch and moulding. Induction brazing is concerned solely with the first of these. Having the correct gap between the base metals is crucial. A too-large gap can minimize the capillary force and lead to weak joints and porosity. Thermal expansion means gaps have to be calculated for metals at brazing, not room, temperatures. Optimum spacing is typically 0.05 mm – 0.1 mm. Before you braze Brazing is hassle-free. But some questions should be investigated — and answered — in order to assure successful, cost-effective joining. For instance: How suitable are the base metals for brazing; what’s the best coil design for specific time and quality demands; should the brazing be manual or automatic?
High Frequency Induction Brazing Diamond Inserts
Brazing Brass To Copper With Induction
Objective: To braze brass end-connectors to copper tubes used in aircraft assembly air lines Material brass end connectors, copper tubes of different diameters
Temperature 1400 ºF 750°C
Frequency 350 kHz
Equipment DW-UHF-4.5KW induction heating system, including a three turn helical induction coil using two 0.33μF capacitors (total 0.66μF)
Process For smaller diameter parts, flux is applied to the entire part and the copper tube to brass joint is assembled using brazing preforms (allowing for the same amount of braze in each joint). The assembly is placed in the coil and heated for 20-30 seconds reaching a temperature of 1400°F. For larger copper tube assemblies, the same process is used, but the braze alloy is stick-fed to the joint to prevent the alloy from flowing out of the joint. A foot switch control is recommended to enable better control of the process.
Results/Benefits
Economy: Power is consumed during the heating only
Consistency: the results of braze joints are repeatable and uniform
