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Green Rot
Effect of Chromium on Hardenability in Medium-Carbon Steels
Common Rockwell Hardness Testing Problems (part 2)
Common Rockwell Hardness Testing Problems
Factors in Quench-Oil Selection
Question on Retained Austenite Transformation
One-Piece Manufacturing Flow (part 3)
| In Part 2, we began answering some of the questions posed in the first part
of this discussion. We’ll conclude these answers here. |
by Daniel H. Herring | November 9, 2011 | Comments (0)
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One-Piece Manufacturing Flow (part 2)
| In
Part 1, we outlined the circumstances and questions surrounding setting up a
one-piece manufacturing flow through a heat-treat operation. We continue that
discussion by answering some of the questions posed in the first part. |
by Daniel H. Herring | November 2, 2011 | Comments (0)
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One-Piece Manufacturing Flow (part 1)
An Open Question to Readers
| Here’s a chance for you, the
reader, to comment on a topic that I consider of relevance to the industry. |
by Daniel H. Herring | September 28, 2011 | Comments (0)
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Use of Ceramic Paper in Vacuum Furnaces
Questions about P-M Heat Treatment
Aluminum Heat Treatment
Residual Stress Considerations on Carburized Gear Wheels (part 6)
Residual Stress Considerations on Carburized Gear Wheels (Part 5)
Residual Stress Considerations on Carburized Gear Wheels (Part 4)
Residual Stress Considerations on Carburized Gear Wheels (Part 3)
Residual Stress Considerations on Carburized Gear Wheels (Part 2)
Residual Stress Considerations on Carburized Gear Wheels (Part 1)
4130 and 4140 Heat Treatments
What Can Cause a High Dew Point Furnace Atmosphere? (Part 2)
What Can Cause a High Dew Point Furnace Atmosphere?
Nitrogen: A Truly Inert Gas?
White Iron (part 2)
White Iron (part 1)
Annealing 1008 Material
Using Ideal Diameter as a Predictor of Q&T Properties
Post-Weld Heat-Treat Question
Discoloration of Stainless Steel in Vacuum Furnaces Due to Humidity
Press Quenching Pressures
Deep-Case Carburizing
Oil Discharge from Quench Tanks
Effect of Hardfacing on Temper Embrittlement
Decarburization in Nitrogen/Methanol Atmospheres
Mineral Hardness Values
Annealing Gold-Plated Stainless Steel
Vacuum Hardening 410 Stainless Steel
Boronizing
Influence of Alloying Elements in Steel: Nitrogen (part 6)
| All steels contain some nitrogen, which can enter the steel as an impurity or as an intentional alloying addition.
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by Daniel H. Herring | January 19, 2011 | Comments (0)
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Influence of Alloying Elements in Steel: Silicon (part 5)
| Varying amounts of silicon are usually present in most steels, up to as high as 15%. Silicon alloyed with steel gives a metal of great soundness and toughness since it is a powerful deoxidizer and removes gases and oxides from steel.
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by Daniel H. Herring | January 12, 2011 | Comments (0)
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Stress Relief of Austenitic Stainless Steels
Flowmeter Basics (part 2)
| We are discussing how to keep our flow measurements (and our heat-treat processes) accurate.
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by Daniel H. Herring | December 22, 2010 | Comments (0)
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Flowmeter Basics (part 1)
| A number of people in the industry take flowmeters for granted. Here are a few simple rules that will help keep our flow measurements (and our heat-treat processes) accurate.
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by Daniel H. Herring | December 15, 2010 | Comments (0)
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What is LMTD?
| The log mean temperature difference (LMTD) is used to determine the temperature driving force for heat transfer in flow systems, most notably in heat exchangers.
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by Daniel H. Herring | December 8, 2010 | Comments (0)
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Types of Vacuum Heat-Treating Equipment (part 3)
| Uniformity of temperature in vacuum furnaces is of great importance to heat-treatment results.
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by Daniel H. Herring | December 1, 2010 | Comments (0)
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Types of Vacuum Heat-Treating Equipment (part 2)
Types of Vacuum Heat-Treating Equipment (part 1)
| Vacuum furnaces can be classified, according to the mode of loading, into horizontal and vertical furnaces and can be batch or continuous (multi-chamber) designs.
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by Daniel H. Herring | November 17, 2010 | Comments (0)
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Types of Atmosphere Heat-Treating Equipment (part 2)
Types of Atmosphere Heat-Treating Equipment (part 1)
| Atmosphere furnaces are characterized by their use of a “protective” atmosphere to surround the workload during heating and cooling.
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by Daniel H. Herring | November 3, 2010 | Comments (0)
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Classification of Heat-Treating Equipment (Part 2)
Classification of Heat-Treating Equipment (Part 1)
| Heat-treating furnaces can be divided into two main types: batch and continuous.
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by Daniel H. Herring | October 20, 2010 | Comments (0)
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Cooling of Metal Parts by Forced Convection
Heating of Metal Parts by Convection
Cooling of Metal Parts by Radiant Heat Transfer (part 2)
Types of Oven Equipment
| Ovens may be designed for intermittent loading (one batch at a time) or for a continuous flow of work using some form of conveyance through the unit.
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by Daniel H. Herring | September 15, 2010 | Comments (0)
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Cooling of Metal Parts by Radiant Heat Transfer (part 1)
Heating of Thin Metal Parts by Radiation (part 3)
Heating of Thin Metal Parts by Radiation (Part 2)
Heating of Thin Metal Parts by Radiation (Part 1)
| When heating thin metal parts that are placed into a hot furnace chamber, it can be assumed that the heat energy that enters the metal surfaces will be by radiation and that convective heat transfer to the center of the part will happen (almost) instantaneously.
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by Daniel H. Herring | August 18, 2010 | Comments (0)
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Liquid Metal Embrittlement
All About Nickel-Based Alloys (part 2)
All About Nickel-Based Alloys (part 1)
Stress Corrosion Cracking, Hydrogen Embrittlement of Nickel Alloys
Weld Cracks in Monel K500
Vacuum Hardening of Tool Steels
Salt Bath Hardening of Tool Steels
Nadcap Advice (Part 2)
Nadcap Advice (Part 1)
All That Glitters…
Causes for Heat-Treat Distortion
A Pictorial Comparison of Nitriding and Carburizing
Tips for Selecting Induction Heating Equipment
Loading Orientations for Gears
Bake-out Cycle After Plating
Gas Carbonitriding
Carbon Flux
A Discussion About LNG and LPG
Heat Treatment of Nitinol Alloys (Part 2)
Heat Treatment of Nitinol Alloys (Part 1)
| Nitinol alloys exhibit two closely related and very unique properties: shape memory and superelasticity (also called pseudoelasticity).
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by Daniel H. Herring | March 17, 2010 | Comments (0)
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Emissivity
Managing Distortion in the Heat Treatment of Gears
MRO (Maintenance Repair Operations)
Variable Hardness Levels for A2 Tool Steel
Annealing to Achieve Soft Parts for Low-Carbon and Stainless Steels
Atmosphere Furnace Leak-Determination Procedure: Copper, Steel, Stainless Steel Test
| The question is often asked, “Do I have an air leak or a water leak in my furnace, and how can I tell them apart?”
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by Daniel H. Herring | February 3, 2010 | Comments (0)
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Atmosphere Furnace Leak Checking Procedure: Smoke Bomb Test
| The following procedure will help you determine if your atmosphere furnace has an air leak.
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by Daniel H. Herring | January 27, 2010 | Comments (0)
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Influence of Alloying Elements in Steel – Manganese (Part 3)
| Last time, we looked at the first 25 influences of manganese. Here are the remaining 25.
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by Daniel H. Herring | January 20, 2010 | Comments (0)
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Influence of Alloying Elements in Steel – Manganese (Part 2)
| With 50 different effects of manganese on steel, we will look at the first 25 this time and conclude next week.
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by Daniel H. Herring | January 13, 2010 | Comments (0)
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Influence of Alloying Elements in Steel – Manganese (Part 1)
Oven Materials of Construction to Resist Hydrobromic Acid Corrosive Attack
Flame Hardening 101
Vacuum Hot-Zone Construction for the Heat Treatment of MIM Materials
Bending Fish Hooks
Tips for Nickel Brazing Two Inconel 625 Parts Using BNi-3 Filler Metal (Part 2)
Tips for Nickel Brazing Two Inconel 625 Parts Using BNi-3 Filler Metal
Tips for a Successful Ammonia Installation
Nitriding of Hot-Forming and Blanking Dies
Considerations in Cooling Large Loads
Precautions When Using Hydrogen for Partial Pressure and Quenching
Experience with Helium and Hydrogen for Partial Pressure and Quenching
Understanding the Bauschinger Effect
Annealing Ductile Iron
How to Achieve Different Mechanical Properties on SAE 4340 at 30 HRC
Heat Treating 440C Stainless Steels
Critical Temperatures for Precipitation Hardening Stainless Steels
Annealing Platinum-Iridium Alloys
Annealing Copper and Copper Alloys
Titanium Nitride Coating for Tools (Part 2)
| A key area of consideration for your selection process is the end-use application temperature of the component that is to be coated.
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by Daniel H. Herring | August 19, 2009 | Comments (0)
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Titanium Nitride Coating for Tools (Part 1)
Segregation and Banding in Steel Revisited
Understanding Pressure Scales (psia vs. psig)
NFPA 86 and Furnaces Operating Below 1400ºF (760ºC)
Decarburization Protection for M-Series High-Speed Steel
Material Science 101: The Polymorphic Nature of Iron
| Iron is “polymorphic.” That is, it has the ability as a solid material to exist in more than one crystallographic form or structure.
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by Daniel H. Herring | July 8, 2009 | Comments (0)
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Nitriding Stop Off
Austempering SAE 1050 Steel
H-Band Boron Steels
Induction Heating of Forgings
Stress Relief (Part 2: Alternative Techniques)
| In Part 1, we talked about what stress relief is, how it is performed in an oven or furnace and talked about a few typical applications. However, there are other ways (typically by mechanical methods) to perform a stress-relief operation than by applying heat.
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by Daniel H. Herring | June 3, 2009 | Comments (2)
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Heat Treatment of Copper-Beryllium Alloys
Sinter Hardening (Part 2: Hardenability Calculations)
Sinter Hardening (Part 1: Alloying Additions)
Stress Relief (Part 1: Steel Components)
| Stress relief is a type of heat treatment used to reduce or remove internal stress induced into metal components from various manufacturing methods.
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by Daniel H. Herring | May 6, 2009 | Comments (1)
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Stead’s Brittleness (Embrittlement)
| Question: “I’ve heard the term ‘Stead’s Embrittlement,’ but I know little about it. Can you tell me what this is, and do you have any examples?”
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by Daniel H. Herring | April 29, 2009 | Comments (0)
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Widmanstätten Structures
| “I’ve heard the term ‘Widmanstätten structure’ but never seen one. What is this?”
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by Daniel H. Herring | April 22, 2009 | Comments (0)
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Charpy “V” Notch Values
The Importance of Soak Time in Magnesium Heat Treatment (Part 2)
| With respect to your application - the tensile strength (Ftu), tensile yield strength (Fty), elongation (e), and sometimes the compressive yield strength (Fcy) are normally called out in your customer's procurement specifications.
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by Daniel H. Herring | April 1, 2009 | Comments (1)
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The Importance of Soak Time in Magnesium Heat Treatment
Grinding Burn Question
| I always assumed you cannot get retained austenite during induction hardening (in this case 4145H steel) since you are only heating to the depth of case and can quickly (more completely) transform the austenite to martensite.
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by Daniel H. Herring | March 18, 2009 | Comments (2)
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Rubber Band Question
Influence of Alloying Elements in Steel: Part 1
| Pure iron is a poor engineering material, often no stronger than most plastics. It is certainly not suitable for use as a structural material and does not respond in any appreciable degree to heat treatment.
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by Daniel H. Herring | March 4, 2009 | Comments (0)
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Benefits of Heat Treating (Part 5): Time-Temperature-Transformation (TTT) Diagrams
| The phase transformations described in "Benefits of Heat Treating" Parts 2, 3 and 4 occur by nucleation and growth and are diffusion-controlled.
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by Daniel H. Herring | February 25, 2009 | Comments (0)
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Question About Soft Spots in Carburizing
A Soft Annealing Question
| I have a question about soft annealing of DIN 1.6582 steel.
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by Daniel H. Herring | February 11, 2009 | Comments (1)
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A Question about Normalizing
| Question: We have a 4340 steel that is used for gear production by our customer. The production sequence is melting, forging, primary heat treatment (normalizing and/or annealing), machining, stress relieving, final heat treatment (surface hardening). To obtain the optimum balance of machinability and high hardness, which will be better for the primary heat treatment, normalizing or annealing?
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by Daniel H. Herring | February 4, 2009 | Comments (0)
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Benefits of Heat Treating (Part 4): Martensite Formation & Tempering
| When austenite is rapidly cooled (i.e. quenched) to room temperature, an unexpected phase transformation can occur.
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by Daniel H. Herring | January 28, 2009 | Comments (0)
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Benefits of Heat Treating (Part 3): Pearlite Formation
| The iron-carbon (or iron-iron carbide) phase diagram – Benefits of Heat Treating (Part 2): Phases of Steel; Fig. 1 – tells us that steel containing approximately 0.76 wt% carbon is at the eutectoid composition.
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by Daniel H. Herring | January 21, 2009 | Comments (0)
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Induction Tempering of Cast Iron
Benefits of Heat Treating (Part 2): Phases of Steel
| A phase diagram is a map used by metallurgist and heat treaters to determine the phase or phases that exist in equilibrium as a function of temperature and composition.
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by Daniel H. Herring | December 23, 2008 | Comments (0)
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Can Quench be Delayed?
Benefits of Heat Treating (Part 1)
| To fully understand the advantages of heat-treating processes to manufacturing it is important to first understand a fundamental principal of metals – structure.
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by Daniel H. Herring | November 4, 2008 | Comments (2)
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Tips on Gas Nitriding: Part 2
The Heat Treat Doctor Talks About Alloy Steel
The Heat Treat Doctor Talks About Plain-Carbon Steel
Tips on Gas Nitriding: Part 1
| A wide variety of steels, some stainless steels and certain tool steels can be nitrided using gas, ion (plasma) or salt-bath methods.
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by Daniel H. Herring | July 25, 2008 | Comments (0)
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How To Avoid Hydrogen Embrittlement
| If as a result of plating or other operations you suspect that hydrogen absorption has taken place in a part, it need not be a permanent condition. If cracking does not occur and the environmental conditions are changed so that no hydrogen is generated on the surface of the metal, the hydrogen can re-diffuse out of the steel and part ductility can be restored.
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by Daniel H. Herring | July 15, 2008 | Comments (1)
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Purging of Furnaces – How Do We Know When It’s Safe?
| The 2007 Edition of NFPA 86 (Standard for Ovens and Furnaces) defines a Class C Furnace as one that “has a potential hazard due to a flammable or other special atmosphere being used for treatment of material in process.”
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by Daniel H. Herring | June 30, 2008 | Comments (0)
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