Interview Questions.

Question 1. What Is The Difference Between Soldering, Brazing And Welding?

Answer :

Brazing - The AWS defines brazing as a group of becoming a member of processes that produce coalescence of materials by using heating them to the brazing temperature and by using using a filler steel (solder) having a liquidus above 840°F (450°C), and under the solidus of the bottom metals. For a closer rationalization, see How Brazing Works

Soldering - Soldering has the identical definition as brazing except for the fact that the filler metal pastes used has a liquidus below 840°F (450°C) and beneath the solidus of the base metals.

Welding - In welding, fusion takes place with melting of both the bottom metal and generally a filler metallic. See our Brazing vs. Welding article for greater in-depth solutions.

Question 2. What Does A Brazed Joint Provide?

Answer :

Brazing provides:

Strong joints
Lower temp/lower cost
Maintains integrity of base metals
Easily joins assorted metals
Good joint look
Skill easily acquired/automatic
Welding Technology Interview Questions
Question 3. How Does Brazing Work?

Answer :

Brazing creates a metallurgical bond between the filler steel and the surfaces being joined. Heat is applied to the base metals and the filler metal is brought into contact with the heated components. When the filler steel melts, it's miles drawn via the joint by capillary motion.

Question four. What Types Of Filler Metal Forms Are There?

Answer :

Filler metals are available in wire, strip, powder, or paste shape. Availability in those paperwork depends at the alloy that is selected. Performs can be crafted from strip and wire.

Question 5. What Is Oxidization?

Answer :

When metals are exposed to oxygen, oxides form from oxygen atoms that attach to the metal. The oxides that shape save you the molten alloy from metallurgically becoming a member of to the metal.

QC Welding Inspector Interview Questions
Question 6. What Is Flux?

Answer :

Flux is a chemical compound this is implemented and shields the joint surface from air and stops oxide formation. Although flux will dissolve and absorb oxides, the metals which are being joined must be properly wiped clean previous to brazing.

Question 7. What Are The Available Flux Forms?

Answer :

Flux is to be had from Lucas-Milhaupt in paste, slurry, liquid, and powder form depending on the sort of flux. Paste, slurry, and liquid fluxes are all water primarily based whilst dispensable fluxes are petroleum based. Flux can also be delivered to the joint through the torch that is being used.

HVAC Interview Questions
Question eight. How Can Flux Be Cleaned Off Of Joint After Brazing?

Answer :

The simplest way to clean flux off the brazed joint is to quench and soak the assembly in hot water. HCl (up to 25%) can be brought to the water for cussed flux residue. Special cleaners can also be bought if needed.

Question nine. What Is The Shelf Life Of Flux?

Answer :

If saved in the unique unopened box, Lucas-Milhaupt flux is below guarantee for 365 days from the date of manufacture. This does no longer suggest that once twelve months the flux is now not useful.

Maintenance, restore and operations (MRO) Interview Questions
Question 10. How Can Flux Be Reconstituted Or Thinned?

Answer :

Water may be used to skinny water-primarily based flux. Usually distilled or de-ionized water is used for this reason.

Question eleven. What Is Brazing Paste?

Answer :

Brazing paste is a fabric which includes steel alloy in a powder shape mixed with a binder. When it's miles required, brazing flux is added to the brazing paste to offer safety from oxidization.

Gas Analyzer Interview Questions
Question 12. In What Applications Is Using Paste Feasible?

Answer :

Paste can be used for torch, induction, and furnace applications. In these programs flux is generally brought to paste system. When using paste in a vacuum or ecosystem furnace flux does now not want to be delivered to the paste.

Welding Technology Interview Questions
Question 13. What Is The Shelf Life Of Brazing Paste?

Answer :

Brazing paste this is in its original unopened box is warranted for ninety days. Similarly to the flux, this warranty does not mean that when the ninety days, the paste will now not characteristic. Functionality can best be decided by way of melting the paste to look if flows or now not. If the alloy flows then it's far nonetheless functional, conversely if the alloy balls up then it isn't practical.

Question 14. What Is The Proper Clearance For Brazing?

Answer :

In wellknown, a joint clearance ranging from zero.002"-zero.Half," will produce sound excessive electricity joints while flux brazing. When atmosphere and vacuum brazing, joint clearance have to be zero.000"-zero.002." Care does want to be taken whilst brazing metals with exclusive coefficients of thermal enlargement. The amount the materials increase desires to be factored in while determining joint clearance.

Question 15. What Types Of Joint Configurations Can Be Used When Brazing?

Answer :

There are numerous different sorts of joints that can be used. The most common of these are butt joints, lap joints, and butt lap joints. Pictures and calculations for determining the duration of a lap joint can be seen by using mouse clicking right here to go to the "Principles of Joint Design" article."

Mechanical Fitter Interview Questions
Question 16. At What Temperature Should The Furnace Be At When Furnace Brazing?

Answer :

Typically the furnace could be heated to a temperature 50°F-100°F above the liquidus of the filler metallic being used.

Question 17. What Is The Strength Of A Brazed Joint?

Answer :

The power of a brazed joint depends on numerous various factors. These being:

The base metals being joined
Joint clearance
Filler metallic used
Joint electricity varies with use of various base metals and filler metals.

Joint power additionally relies upon on the space among the two metals being joined. When the distance is multiplied the joint strength decreases. Often instances, under the precise situations, the braze joint energy might be identical to or more than the power of the base metals. For more in-intensity data on the sorts of brazed joints, see our article on brazing joint design.

Pipe Fitter Interview Questions
Question 18. What Is Handy One?

Answer :

HANDY One is a flux cored product that simplifies the brazing technique. HANDY One is a brazing alloy in strip shape rolled around a measured quantity of powdered flux. As the element is heated the flux is released imparting protection from oxidation. It is available in a couple of filler metals and flux combinations to sign up for absolutely all common metals.

QC Welding Inspector Interview Questions
Question 19. What Alloy Is Recommended For Brazing Copper To Copper?

Answer :

In maximum instances, when brazing copper to copper in air con and refrigeration carrier, considered one of our SIL-FOS alloys would be encouraged. The phosphorus within the alloys allow the SIL-FOS organization to be self fluxing while brazing copper to copper which eliminates the usage of a separate flux.

Question 20. Can Stainless Steel Be Brazed In Vacuum Below A Temperature Of 1700° F?

Answer :

Stainless can not be vacuumed brazed in at a temperature underneath 1700° F due to the possibility of chrome-oxide formation which will restrict the glide of the filler metal alloy on the stainless steel. A brazing temperature of as a minimum 1750° F is usually endorsed in vacuum for stainless steel. If the chrome steel is nickel plated it may be brazed at temperatures lower than 1700° F.

Question 21. What Braze Alloy Would Be Appropriate For Brazing three hundred Series Steel That Will Be Subjected To Contact With Water?

Answer :

When brazing stainless steels with a view to be uncovered to water, an alloy must be used that consists of nickel. Examples of those might be EASY-FLO® three, Braze 505, Braze 630 and Braze 403. The nickel in these alloys allows limit interface corrosion inside the metal. To learn more about interface corrosion please read Technical Bulletin No. T-9 or contact Lucas-Milhaupt Technical Service.