High Strength NITRONIC 60 Bridge Hinge Pins

by Grant Kirchner

High Performance Alloys, a distributor of NITRONIC 60 and producer of high strength NITRONIC 60, makes bridge hinge pins for use in high strength applications. Not only is NITRONIC 60, a chromium nickel stainless steel, good for high strength, but it also has good corrosion resistance and great galling resistance. These characteristics of the high strength steel help it to be very effective in construction projects such as bridge repairs and construction. 


The galling resistance is a tremendous bonus to the alloy over other stainless steels as the pin must be able to move with the expansion and contraction of the bridge. The ability of NITRONIC 60 to resist galling and corrosion are tremendous advantages in high strength applications for the continuous lifecycle of a bridge.

High Performance Alloys has produced high strength NITRONIC 60 to over 200 KSi yield. High Performance Alloys is also a domestic distributor, stocker of NITRONIC 60 that allows for quicker turnaround times here in the United States.

NITRONIC is a registered trademark of AK Steel.

Read an interesting datasheet on ACUBE 100 today

The datasheet on AMS 5918 (ACUBE 100) indicated that the ductility of the material is severely impacted from even a small amount of cold work : Cold Working

High strength levels can be achieved in ACUBE 100 alloy through cold working processes. It should be noted that a significant loss of ductility results from even small amounts of cold work. Taken from http://cartech.ides.com/datasheet.aspx?i=101&c=TechArt&E=341 on 10/28/2014

After locating the material specification in a cold formed bushing requirement, I was interested in what the AMS 5918 was. I was even more surprised after reading the above excerpt. The AMS 5918 is the warm worked variation (in certain cases, warm working can have undesirable precipitates occur). Warm worked materials have 7 to 30% Elongation and 10 to 24% Reduction of Area.  These low Elongation and Reduction of Area numbers indicate a stiffness or brittleness that would indicate fatigue and shock resistance may be an issue.

Wear and galling resistance is toted as primary benefits of the grade, but it has a very low galling threshold. Galling threshold is listed as greater than 20KSI. While the >20KSI threshold (per ASTM G98) is impressive when compared to type 316 which is >1KSI and 440C only attains 18KSI, it is also telling when MP35N has a threshold of 5KSI. I must note that NITRONIC 60 in the annealed condition (AMS 5894) has a threshold of >50KSI (primarily dictated by its yield strength, rather than an overall hardness achieved).

We perform hot, warm and cold forging processes in Tipton on our various equipment, so its always good to stay abreast of materials that are being utilized by industry.

Forging super alloy and super stainless

Forging super alloy and super stainless is not an easy job. Working these alloys usually requires twice as much power as other alloy or stainless products. This is due to the alloys being very strong through their chemical composition - higher alloy grades inherently have greater value. That inherent value is before you even cut it, heat it and form it to the shapes and sizes required. Having the right size billet starting stock makes a difference in the overall forging time required and the resultant mechanical properties the item will have. The chances a forging house will be able to make a small part successfully is dependent upon the input billet, how many pieces regularly required and over how many years it will run.

When requesting a quotation for a forging, it is very helpful to provide the finished dimensions, and allow sales to provide the oversize amount needed to guarantee the part can be machined. It may be more stock to remove than you would like, but you should only have to machine it once. Some materials are tougher to forge and machine than others. If you have never machined the item before, this is a good time to talk to sales about machinability and tooling needs. Many times machine shops will win an order due to machine time underestimate. Some of these alloys will take twice as long to machine, due to the removal rates are not as good with the higher tensile and yield strengths.

Forgings can be provided in a multitude of ways and they have different amounts of value added service. Forging option for open die forgings are as follows: oversized with allowance to finish, rough ground, rough machined, and finish machined per print. We also can perform inspections at this stage (above and beyond the AMS/ASTM material requirements). Whether it is an ultrasonic to various criteria, charpy V notch, magnetic permeability, dye penetrant or radiograph - it is always best to use these types of inspections early when they can be performed early and with less complex geometry.

Most of our customers require actual mechanical testing for their forgings. The controlling specification would have an indication of whether testing is required, but the application or usage of that part is what should dictate the need. A non critical part could be verified that is has been supplied correctly through a simple hardness check. The options for actual mechanicals are testing from a forged coupon, using a prolongation of the piece or cut from item, and actually destroying a piece to determine properties.  Separately forged test coupons are normally the route taken, and provide a great insight to the properties of the actual forging. The actual forging should be hardness tested and compared to the coupon hardness to correlate the two properties. Using a prolongation or destroying the sample will provide results that can certify a batch as well, these would be used for more critical type requirements and help show how the material is responding in "as used" cross sections.

A Few “Must-Knows” About Our Company

   Tipton Forging is a division of High Performance Alloys, located in Tipton Indiana. If you were to call us today, the phone will be answered by a High Performance employee - so please do not be confused. High Performance Alloys (HPAlloy) is a small family owned company, serving the aerospace, nuclear, marine, chemical and petroleum industries since 1984. HPAlloy started out as a service center, primarily serving the small quantity needs of many shops across the country. No one company needed a great amount of the products we carried, but the one thing they had in common was the need to repair or build small quantities of these materials into their projects. They needed small cuts and short lengths quickly. Thirty years ago, business was done by phone and mail, a formal quote would take over a week to receive.

  We have a great following of customers and friends from over the years. The main company has grown and grown, but most people think of High Performance Alloys for stock needs quickly. We needed to get the message out to the public about the added capabilities of the company, and so a division was born to serve that purpose. The one main difference between the divisions is that Tipton Forge has a basic concept to forge materials quickly and make specialty items in prototype quantities even faster. Historically, the mills had research and development departments that would take care of some of these needs. Unfortunately, most of those R&D departments are only shells of their former selves. They can do some things, but they don't have the manpower required to act quickly anymore. Research and development of materials in the country has been stagnated. There are still needs to have small to medium quantities of items specially produced. That is where we come in, and that is a niche we have been filling for the last twenty years at our own facility. Our company's founding metallurgists had been serving these needs unknowingly since the beginning, only they had no idea the places they would have things made would eventually be phased out or consumed by larger corporations.