Keyword

Essential Criteria for Brazing: Item 5 – Fixturing: Use of Thermocouples in Furnace Brazing (Part 2)

Essential Criteria for Brazing: Item 5 – Fixturing: Use of Thermocouples in Furnace Brazing (Part 2)In this month's article, we will look further at the placement of TC's in furnace brazing loads, and how, together with correct furnace heating/cooling rates, they can help to maximize uniformity of temperature throughout each brazing load and minimize any distortion of the components being brazed.

To have good control of any furnace-brazing process-run, you will need to know the temperature of the parts being brazed inside the furnace, and in batch-type furnaces this can only be done via well-placed thermocouples (TC's) throughout the furnace and in the load of parts being brazed.

 

Essential Criteria for Brazing: Item 5 – Fixturing: Use of Thermocouples in Furnace Brazing (Part 1)

In this month’s article, we continue to look at methods you can use to keep fixturing-weight down to a minimum, especially in furnace brazing, remembering once again that fixtures (baskets, frames, grates, dead weights, etc.) represent a large mass of metal (the material most often used in fixturing) that absorbs a lot of heat and can thus significantly increase the brazing time needed to complete a braze. Make it your job to significantly reduce the amount of fixturing-weight put into your brazing furnace.

In last month’s article, I mentioned that someone increased the productivity of their brazing operations by over 75% when they implemented the fixturing recommendations  I made to them during the brazing-seminar they attended (the same recommendations I’m making in this article).

 

Essential Criteria for Brazing: Item 5 – Fixturing: Keeping weight to a minimum (Part B)

In this month’s article, we continue to look at methods you can use to keep fixturing-weight down to a minimum, especially in furnace brazing, remembering once again that fixtures (baskets, frames, grates, dead weights, etc.) represent a large mass of metal (the material most often used in fixturing) that absorbs a lot of heat and can thus significantly increase the brazing time needed to complete a braze. Make it your job to significantly reduce the amount of fixturing-weight put into your brazing furnace.

In last month’s article, I mentioned that someone increased the productivity of their brazing operations by over 75% when they implemented the fixturing recommendations  I made to them during the brazing-seminar they attended (the same recommendations I’m making in this article).

Essential Criteria for Brazing: Item 5 – Fixturing: Keeping weight to a minimum (Part A)

We look now at the fifth of the seven important criteria for good-brazing that are listed in Table 1, namely, the use of fixtures in the brazing process. Fixtures hold the parts being brazed, whether it is a metal vice holding parts for torch brazing, or a large furnace-grate on which parts are set for furnace-brazing, just to name two types of fixtures. The important thing to always remember about fixtures is that they usually represent a large mass of metal (the material most often used in fixturing) that absorbs a lot of heat and can thus significantly increase the brazing time needed to complete a braze.

Fixturing. People often do not have a proper understanding of the roll of fixtures in brazing. It can, in fact, have a significant effect on the performance and profitability of any brazing process, be it an operation performed by torch, induction, or furnace. I recently had someone tell me that when they had implemented the fixture-recommendations they learned from my brazing seminar that they had attended, the profitability of that brazing operation went up over 75%. Yes, fixturing is a very important topic that needs to be evaluated thoroughly and properly implemented to optimize your brazing operations.

Essential Criteria for Brazing: Item 4c – Brazing filler metal (BFM) - How much should be used?

We return this month to our series on the essential criteria for brazing, to complete our current series on some fundamental issues about brazing filler metals (BFMs). As was discussed in my previous article on Essential Criteria for Brazing, if you are using BFM powder in your operations, it’s essential to not only control the mesh size of the BFM powder you are using (covered last time), but also to know and specify the ratio of BFM powder to the gel-binder in the brazing paste.   The gel-binder is cellulose-type gel-like substance added to the powder to form a creamy blend of powder and gel that can be extruded from a cartridge through a dispensing tip.  So, whether you are using BFM powder directly, or are using a pre-formed shim/ring of BFM, or BFM in paste form, you must always ask yourself this simple question: “how many times can I fill the braze joint with the BFM that I am using?” Hmmm….   The obvious answer is “one time” only! No matter how good you are, you cannot cram any more BFM into the joint after that joint has been filled by the molten filler metal ONE time! by Dan Kay

answers-kay-associates-brazing-quiz

 

This quiz was not as easy as many of you may have thought. I chose a number of questions that I knew would “challenge” many of you to more clearly think about some of the principles of brazing, and how it works, especially as it might compare to welding. Over my 45-years of teaching brazing and working with it extensively – hands-on — in the field, I’ve seen a lot of “misconceptions” out there about brazing and how it should be correctly applied. I hope this quiz has challenged some of your own thinking on the topic, and opened your eyes and thinking to some new things about brazing you did not know before. Let us each continue to work hard to apply brazing correctly in our (and our customer’s) work, so that brazing will be more correctly applied and understood.

Last Updated on Tuesday, 20 June 2017 14:56

Hits: 717

Read more: answers-kay-associates-brazing-quiz

Essential Criteria for Brazing: Item 4a – Brazing filler metal (BFM) powder used in making brazing-paste.

IMPORTANT NOTE: The Brazing Quiz published in our April column is STILL open for readers to try. Because only a few people actually sent in their replies, we encourage more of you to do so. We’ll then publish the answers in the June column (next month).

We return this month to our series on the essential criteria for brazing, and will look more closely at another aspect of brazing filler metals (BFMs). If you are using BFM powder in your operations, then it will be very important for you to understand and to control the mesh size of the BFM powder you are using, since powder mesh size can affect brazing performance.

A common way to create BFM powder is by melting the raw ingredients for the BFM in a large melting pot using induction heating, and then pouring the resulting liquid metal through a specialized atomization nozzle in which a very high-pressure gas will literally blast the molten metal stream into billions of tiny particles (inside an atomization chamber). The tiny particles will fall by gravity to the bottom of the chamber, solidifying along the way into solid powder particles.

Log in to your account or