Home/Questions Feed

Vacuum Furnace End-User Q&A Community Latest Questions

Bryan R Cope
  • 1
Bryan R Cope
Asked: March 2, 2023In:
  • 1

Replacing our hot zone in a 36 x 24 x 24 inch furnace.  The insulation is fiber. The furnace does high speed steel at 2175 F. What would be a typical burn in cycle?

  1. Raf Walczak

    Furnace burn out (a.k.a. thermal cleaning) cycles are important part of vacuum furnace maintenance. It is meant to reduce and outgas contaminants inside the heating zone and within the insulation. For new hot zone it is more related to drying, conditioning and outgassing the remaining resin from insRead more

    Furnace burn out (a.k.a. thermal cleaning) cycles are important part of vacuum furnace maintenance. It is meant to reduce and outgas contaminants inside the heating zone and within the insulation.

    For new hot zone it is more related to drying, conditioning and outgassing the remaining resin from insulation manufacturing processes. Every new furnace should be burned out at it’s nominal temperature and I’d say this rule should also apply to any hot zone replacement. Your hot zone supplier should be able to tell you the nominal temperature of the hot zone.

    Duration of burnout should be at least 2 hours at the temperature, however you may keep it longer if you see continuous improvement of furnace vacuum level.
    Slow cooling is recommended after burnout.

    IMPORTANT: The burn-out cycle is always performed with empty furnace. any tooling / fixturing and other equipment must be removed otherwise serious damage of furnace and tooling may occur.
    For your own safety you should follow the OEM manuals.

    See less
    • 1
MERT
  • 1
MERT
Asked: March 2, 2023In: , , ,
  • 1

I HAVE A CONTAMINATION PROBLEM WITH THE VACUUM FURNACE. WHEN I  LOAD CHARGE TOOL STEELS ARE TRANSFORMİNG THİS COLOUR. DOES ANY BODY HAVE AN IDEA? WHAT SHOULD BE THE FIRST STEP ?

  1. VacuumFurnaces.com Answers

    "When operating vacuum furnaces, situations may arise in which the hot zone and/or cold walls may become contaminated (Fig. Nos. 1 – 2). This can occur from a variety of sources: air leaks, outgassing from residues left on the parts as a result of the manufacturing or cleaning processes, vaporizatioRead more

    “When operating vacuum furnaces, situations may arise in which the hot zone and/or cold walls may become contaminated (Fig. Nos. 1 – 2). This can occur from a variety of sources: air leaks, outgassing from residues left on the parts as a result of the manufacturing or cleaning processes, vaporization of sensitive materials (e.g., chromium-bearing materials), process-induced contaminations such as carbon in the form of soot or tar, fluxes from brazing pastes, excess braze alloy as well as many other sources. Often times the work being processed is also affected (Fig. 3). The question becomes, how do we attempt to clean up our contaminated vacuum furnaces? >>>Read More

    Source: VAC AERO International

    See less
    • 1
DSnell
  • 0
DSnell
Asked: January 22, 2023In:
  • 0

I have a Class 1 aluminum vacuum brazing furnace (per AMS2750 G) that has seven zone thermocouples. When performing a system accuracy test (SAT), must I verify all seven zone temperatures are within ±2° F of the SAT thermocouples installed ...

sattc
  1. Raf Walczak

    According to paragraph 3.4.1.2. of AMS2750G: "The SAT shall be performed on all control and recording systems required by the applicable instrumentation type, as well as any additional recording systems used for parts and raw material acceptance in each control zone of each piece of thermal processiRead more

    According to paragraph 3.4.1.2. of AMS2750G:
    “The SAT shall be performed on all control and recording systems required by the applicable instrumentation type, as well as any additional recording systems used for parts and raw material acceptance in each control zone of each piece of thermal processing equipment used for production heat treatments.”

    That means you should perform SAT on all control temperatures as well as any other temperature measurement system which are required by instrumentation type. For example Load thermocouples for instrumentation type A and B.
    SAT is not required for overtemp systems (if overtemp protection  is the only function of that system).

    Each of those ‘systems’ (Thermocouple, TC wires, feedthroughs, and measuring/recording instrument) should be within SAT tolerance (which is 2F for class 1 equipment) to their SAT sensor.

    See less
    • 1
Load More Questions