Eurotherm sponsored the august edition of the online newsletter from themonty. To view click on the above picture or the following link http://themonty.com/newsletters/themontyaugust10.pdf

The graph illustrates that some Nitrided steels have a higher surface hardness than Carburized steels but a lower overall total case-depth. The higher hardness comes from combining Nitrogen and alloying elements in the steel and usually for straight Nitriding you would use what is termed as an alloyed steel. For Carburized steels you would normally use a lower alloy steel (unless Vacuum or Low Pressure carburizing). 

 Typically the higher the alloy content of the steel, the higher the cost of the base material. The Nitriding process CAN be a more costly process to run based on batch processing and long cycle times. However, other benefits of the Nitrided process such as lower temperature giving less distortion, additional strength properties from an alloyed steel, higher hardness (can lead to higher wear resistance) and other material properties can help to offset these costs.

For basic components that require some improvement in material properties, generally the lower cost treatments are to harden and temper (through harden) or carburize to shallow depths. However,  engineered components require more sophisticated processing that may result in additional costs but as previously explained this is more than offset by the increase in the material properties that result from the treatment.

Please see below the graph of Hardness versus Case Depth – this is from Dan Herring’s blogposts in Industrial Heating (see reference below, or click on graph to go to original article). HRc 60 is a hardness measurement on the Rockwell C scale, typically this value is the benchmark for a carburized steel, I remember when I started out in heat treatment we would sometimes use ‘hardened metal files’ and rub these across a surface of the carburized steel to check if the steel had sufficient hardness (file would polish) or if the surface was poorly treated and had low surface hardness, the file would scratch/dig-in to the surface of the steel.

 Figure 5. Typical gear tooth hardness profiles[2]

A Pictorial Comparison of Nitriding and Carburizing
by Daniel H. Herring
May 12, 2010

Industrial Heating supplies RSS feeds to many of its new broadcasts, one such feed which I find very useful to keep updated is the “The Experts Speak” section and in particular the posts by Dan Herring – Heat Treat Doctor.

I am using an RSS feed to Dan’s posts at the bottom of this blogsite which will maintain a live link through to any updates that Dan posts. Please scroll down to the bottom of this site to keep updated with valuable information from the Heat Treat Doctor or alternatively visit Industrial Heating directly through  http://www.industrialheating.com/Articles/The_Experts_Speak?view=rss

Thanks to Dan for keeping the Industry updated with crucial information!

Join our Linkedin Heat Treatment Group by pressing the button below and following the onscreen prompts.

Take Control of Your Accuracy article in Process Heating, June 2010.

Please click on the above link to see a recent arcticle (June 2010) that we wrote for Process Heating regarding accuracy of DIN style Controllers and in particular focusing on meeting the AMS2750D standard.

You will also see a comments balloon to the top right of each blog post - this is either feedback received about the posts or further information in the thread of the subject.

Also right at the bottom (footer) of the page – you will need to scroll down – you will find links to the facebook page, number of visitors to the site and also an RSS feed from the Industrial Heating Website which is following posts by Dan Herring – the Heat Treat Doctor. 

I hope you enjoy the new design.