Arvind Thekdi - E3M, Inc. Sales Supplementary Information Supplementary Information Heat Treating...

Arvind Thekdi - E3M, Inc.Sales

Supplementary InformationSupplementary Information

Heat Treating Industry, Processes and Equipment

A seminar Presented for Southern California Gas Company

Sales Staff

February 20th, 2002

Presented By Arvind C. Thekdi - E3M, Inc.

Supplementary InformationSupplementary Information

Heat Treating Industry, Processes and Equipment

A seminar Presented for Southern California Gas Company

Sales Staff

February 20th, 2002

Presented By Arvind C. Thekdi - E3M, Inc.


Specific Effects of Steel Heat Treating

• Improve the Toughness

• Increase the Hardness

• Increase the Ductility

• Improve the Machineability

• Refine the Grain Structure

• Remove the Residual Stresses

• Improve the Wear Resistance


Heat TreatingProcessing Equipment

Gas Fired Furnaces


HeatTransfer

Heat Containment

Heat

Recovery

Energy Source

(fuel, electricity, etc.)

HeatGeneration

Exhaust Gases

MaterialHandling

Air

Process Atmosphere

MaterialHandling

Heat Treating Furnace


Heat to work20% to 40%

Flue gas losses35% to 65%

Wall losses10% to 20%

Fixtures, Baskets etc15% to 40%

Heat Storage5% to 20%

Tota

l H

eat

Inp

ut

10

0%

Atmosphere Losses 5% to 10%

Heat Distribution in a Gas Fired Furnace

(Typical)


Type of Heating Equipment By Material Handling

ContinuousContinuous

• Belt Conveyor (Mesh or Cast)

• Pusher Tray

• Roller Hearth

• Rotary Hearth

• Rotary Retort (Kiln)

• Shaker Hearth

• Overhead Conveyor

• Walking Beam

BatchBatch

• Box Furnaces

• In & Out (Integral Quench) Furnaces

• Bogy or Car-bottom

• Gantry Furnaces

• Bell Type

• Pit Furnace

• Fluidized Bed

• Salt Bath


Continuous

• Belt Conveyor (Mesh or Cast)

• Pusher Tray

• Roller Hearth

• Rotary Hearth

• Rotary Retort (Kiln)

• Shaker Hearth

• Overhead Conveyor

• Walking Beam




Batch

• Box Furnaces

• In & Out (Integral Quench) Furnaces

• Bogy or Car-bottom

• Gantry Furnaces

• Bell Type

• Pit Furnace

• Fluidized Bed

• Salt Bath


• Batch Furnace With High (2 to 100 Tons) Capacity Used in Mills and Heat Treat Shops.

• Primarily Used for Annealing of Ferrous and Non-ferrous Strip or Wire Coils.

• Can Be Operated With a Variety of Atmospheres Including 100% Hydrogen.

• Integral Cooling Coils to Provide Accelerated Load Cooling.

• Includes High Capacity Fan to Provide Convective Heating.

Radiant Tube

Burner Outside a Muffle

Muffle or Cover

Bell Type Furnaces


Radiant Tube Heated Vacuum Furnaces

• The load is heated in vacuum in absence of any type of gases.• Usually batch type furnaces.• Used for special heat treating processes .


Fluidized Bed Furnace

• Consists of a Heat Resisting Retort Heated by Gas Fired Burners or Electric Heating Elements.

• Contains “Sand” Bed That Is Fluidized With Proper Velocity of the Required Atmosphere.

• Used for Small Parts.

• Can Be Used for a Variety of Heat Treating Processes.

• Gives Excellent Heat Transfer and Temperature Uniformity.

• Can Be Designed to Give High Efficiency and Low NOx Emissions.


Pit Furnace

• Batch Type Furnace

• Underground

• Radiant Tube or Electric Heating

• Relatively Low Heat Losses Due to Good Insulation

• Used for Large or Large & Long Loads

• Typical Loads Include Turbine Shafts, Gears, Pipes, Oil-fieldComponents


Other Commonly Used Furnaces

• Retort Furnace (revolving)

• Shaker Hearth Furnace

• Car Bottom Furnace

• Tip-up furnace

• “Gantry” Furnace

• Muffle Furnace

• Box Furnace

• Slot Furnace

• Salt Bath Furnace


Radiant Tube Heated Continuous Furnace

• A Continuous Carburizer for Heat Treating Large Volume Small Parts.• Uses a Variety of Material Handling Methods (Belt, Rollers, Rails, Etc) and Trays, Baskets or Fixtures to Hold Parts.


Process Atmospheres for Process Atmospheres for Heat Treating Heat Treating

Process Atmospheres for Process Atmospheres for Heat Treating Heat Treating


Natural Gas or Ammonia Based Heat Treating Atmospheres

Use Natural Gas – Air Reactions or “Cracking” of Ammonia

To produce the required gas composition


Lean or Inert Exothermic (Exo) Gas

• Purging and Blanketing of Furnace Vestibules, Chemical Tanks, etc.

• Annealing of Non-ferrous Alloys

• Tempering & Bluing of Medium Carbon Steel (0.2% to 0.5% C)

• Bluing of Silicon Steel Laminations, Electrical and Tool Steel

Where are they used?

• Combustion of natural gas and air at near sub-stoichiometric*

conditions

• Water vapor removed from the products of combustion (flue gases)

How are they made?

* Sub-stoichiometric means that air flow to the burner is less than what is required to complete combustion


Rich Exothermic (Exo) Atmosphere

• Annealing of Forged Blanks

• Annealing and Normalizing of Low to Medium Carbon Steels

• Bright Annealing, of Low Carbon (up to 0.2% C) Steels

• Motor Lamination Annealing

• Copper Brazing

• Sintering of Low Carbon Powdered Metals


• Combustion of natural gas and air at sub-stoichiometric – rich*

conditions

• Water vapor removed from the products of combustion (flue gases)

How are they made?



Purified Lean and Rich Exothermic Gas

• Lean: Substitute for Commercial Nitrogen

– Annealing of Malleable Iron

– Purging of Furnaces, Tanks With Flammable Liquids

– Food Storage

• Rich: Substitute for Low Dew-point N2-H2 Mixtures in Heat Treating

– Powder Metal Sintering

– Bright Annealing of Non-ferrous Metals

– Annealing of Medium and High Carbon Steels


• Combustion of natural gas and air at or near sub-stoichiometric*

or at rich conditions

• Water vapor and carbon dioxide removed from the products of combustion (flue gases)

How are they made?



Endothermic (Endo) Atmosphere(High Dew point)

• Carburizing, Brazing and Sintering of Low to Medium Carbon Steel

• Bright Annealing, Carbon Restoration and Brazing of Medium and High Carbon Steels

• Annealing, Clean Hardening of Tool Steels and High Alloy Steels

• Sintering of Powder Metal Parts


• Products of reaction of natural gas and air at rich (highly sub- stoichiometric) conditions in presence of a catalyst in an externally heated reactor or tube.

• External heat supply is required for production of endothermic atmosphere

How are they made?



Dissociated Ammonia Atmosphere

• Brazing and Sintering of Low Carbon Steels

• Rapid De-oxidation of Metal Surfaces

• Purification of By-product Nitrogen for Annealing

• Bright Annealing of Stainless Steel, Silicone Steel

• Sintering of Stainless Steel


• Dissociation (cracking) of ammonia (NH3) into nitrogen(N2) and hydrogen(H2) in presence of a catalyst in an externally heated reactor or tubes.

• External heat supply is required for production of dissociated ammonia atmosphere atmosphere

How are they made?


Concerns About Generated Process Atmospheres

• Fixed composition

– Lack of flexibility in gas composition

– Variations in composition with turn-down

– Difficulty in control

– Dependent on natural gas composition that may vary seasonally

• High capital investment

• Resources required for operation and supervision.

• Lack of reliable automation

• Periodic maintenance (soot burnout etc.) requirements

• Cost of repairs and maintenance for internal parts


Industrial Gas Based Atmospheres


Industrial Gas Based Process Atmospheres

“Sold” as:

• “Engineered” Atmosphere

• Deliver Optimum Atmosphere to Meet Specific Application

• Flexibility in Delivery Options: PSA or Membrane Systems, Storage of Liquid Gases, Pre-scheduled Delivery, Service Etc.

• Extremely Low (< - 90 F) Dew Point and Low (<5 ppm) Oxygen

• Precise Control of Dew-point and ppm Oxygen Levels at All Flows

• Lower Overall Cost Per Application (is Claimed!)

• Little or No Capital Investment

• Automated Operation

• Total Responsibility for Delivery - No Need for an Operator or Maintenance Personnel for Generators


Comments and Considerations

Industrial Gas Based Process Atmospheres

vs. Natural gas Based Atmospheres

In most heat treating operations cost of natural gas based

atmosphere is lower than total cost of industrial gas

based atmosphere

The total cost calculations must include factors such as:

– Cost of gases as delivered and price changes

– Cost of equipment rental and maintenance

– Costs related to minimum gas usage and payment

– Use of utilities related to production and/or distribution of the gases

– Surcharges such as electricity cost

– Cost of commitment for minimum contract period


Cost Comparison Endothermic Atmosphere vs. Nitrogen-Methanol

Fuel Fired Generator Liquid Nitrogen Methanol

Amount Cost Amount CostBasis 1000 cu.ft./hr.

Natural gas for reaction 200 cu.ft. $0.90Vaporized N2 400 cu.ft. $1.20Liquid Methanol 2.55 Gallons $2.04N.G. to vaporize and dissociate methanol in furnace

120 cu.ft. $0.54

N.G. to supply heat in the generator

125 cu.ft. $0.56

N.G. to heat endo gas in furnace

64 cu.ft. $0.29

Electrical power 1.5 Kw $0.11Other - maintenance $0.14 $0.64

Total $2.00 $4.42

CostsNatural gas $4.50 1000 c.f.Nitrogen $3.00 1000 c.f.Methanol $0.80 per gallonElectricity $0.07 per KwhMaintenance $30.00 per hour


Electrical Heating Systems

for Heat Treating

Electrical Heating Systems

for Heat Treating


Resistance Electrical Heating Systems

Shapes: Rods, wire, shaped strips, etc. Directly exposed or inside in an enclosure (tube) Size Range: Available in a wide variety of diameters,

lengths and width


Who are Vacuum Furnace Customers?

• 30% of All Heat Treaters Use at Least One Vacuum Furnace.

• 25% of Customers Plan to Add Vacuum Equipment During the Next 5 Years.

• Approximately 3,000 to 4,000 Vacuum Furnaces Are Used in U.S. and Canada.

• Approximately 100 to 300 Vacuum Furnaces Are Installed in U.S.

• Primary Users: Aircraft and Aerospace.

• Growth Area: Tool and Die Makers and Automotive.


Other Vacuum Applications

• Plasma Nitriding

• Plasma Carburizing

• CVD Coatings


Induction Heating

Major Advantages

• Low Scale and Scrap (Decarb, Distortion, etc.) Losses

• Lower Life-cycle Cost

• “Precise” or Better Control and Automation

• “Cool”

• Less Space - Smaller Foot Print

• Simpler Material Handling

• Ease of Start-up and Shutdown

• “Safe”

• Better Metallurgical Results

Induction 214991Induction 214991


Induction Heating


Major Disadvantages

• High Capital Cost

• High Energy Cost

• Lack of Flexibility for Production Parts Shape and Size

• Not Recommended for Progressive Heating, and Large and Complex Parts

• Requires “Specialized” Maintenance Skills & Personnel

• Not Recommended With Special Atmospheres


Induction Equipment for Metal Heating



Selected Sources for Information

Burner companiesAddress Phone Fax contact Web address

Eclipse, Inc.1665 Elmwood Road, Rockford, IL 61103

815.637.7217 815.877.3443Mr. Jim Roberts

www.eclipse-inc.com

Kromschroder, Inc.1691 H Georgetown Road, Hudson, OH 44236

216.342.0595 216.342.0595Mr. George Paulonis

www.kromschroder.com

Maxon, Inc.201 East 18th St. Muncie, IN 47302

765.284.3304 765.286.8394Mr. Andy Jones

www.maxoncorp.com

North American Mfg. Co.

4455 E. 71st. Street Cleveland, OH 44105

216.271.6000 216.641.7852 Mr. David Gray

Pyronics, Inc.17700 Miles Avenue Cleveland, OH 44126

216.662.8800 216.663.8954 Mr. Tom Jarvis www.pyronics.com

WS Thermal Process Technology Inc.

719 Sugar Lane Elyria, OH 44036

440.365.8029 440.365.9452Mr. Joachim Wunning

www.FLOX.com

Furnace CompaniesAddress Phone Fax contact Web address

Abar Ipsen IndustriesP.O. Box 6266 Rockford, IL 61125

815.727.7625 815.332.4995Mr. Bill Kirchner

www.ipsen-international.com

AFC-Holcroft12068 Market Street Livonia, MI 48150

313.591.1000 313.591.6443 Mr. Jack Titus www.holcroft.com

Lindberg, A General Signal company

304 Hart Street Watertown, WI 53094

920.262.3993 920.262.3815Mr. Patrick Weymer

www.lindberg-bluem.com

Surface Combustion, Inc.

1700 Indian Wood Circle Maumee, OH 43537

419.891.7150 419.891.7151 Mr. Max Hoetzl www.surfacecombustion.com

Seco Warwick Meadville, PA 16335-3618 814.332.8400 814.724.1407 Mr. Paul Huber www.secowarwick.com

Wellman Furnace Company

1 Progress Road Shelbyville, IN 46176

317.392.5268 317.392.5461Mr. Bob Walton

www.wellmanfurnaces.com


GlossaryBatch furnace A type of furnace in which tha parts are kept at one place during heaitng

process

Captive heat treater A company that performas heat treating operation on parts used for its own use

Carburizing A heat treating procsses that forms a hard iron-carbide layer on surface of a part to reduce wear of the part surface.

Commercial heat treater A heat treating services company that provides services to a number of customer companies

Continuous furnace A type of furnace in which tha parts are continuously moving from one end to another end during heaitng process

Induction heaitng Heating of metal parts with magnetic fields generated in the part by using electric current

Integral quench furnace A heat treating furnace that is used for heating and cooling (quenching) of parts

Limiting orifice A type of orifice or a valve used in gas supply line to limit maximum flow of gas that cen be supplied to a burner

Metering orifice A type of orifice or a valve used in gas supply line to measure (meter) flow of gas supplied to a burner

Nitriding A company that performas heat treating operation on parts used for its own use

Protective Atmosphere A heat treating procsses that forms a hard iron-nitride layer on surface of a part to reduce wear of the part surface.

Recuperator A heat exchanger that is used to transfer heat from furnace flue gases to combustion air used in the burners

Vacuum furnaces A type of furnace in which vacuum is maintained during heating and cooling operation

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