Any plating process can produce hydrogen, and in hard parts such as industrial fasteners an uncontrolled process can lead to hydrogen embrittlement. This has been a major cause of fastener failure in the field for many years, and in some cases was the domino that led to major incidents that cost workers’ lives and completely shut down facilities.
Due to this serious threat, the industry has come out in favor of manufacturing and coating standards that prevent hydrogen from infiltrating micro-cracks in the substrate. Many bolting and coating companies bake their parts in high temperatures to evaporate the hydrogen that clings to the surface, and Doxsteel is no different. But that’s not all we do.
First, we have designed additives which reveal hydrogen bubbles and draw them to the surface to be released in the bath. This gives the hydrogen less opportunity to compromise the bolt’s integrity. Second, we constantly test all elements of the plating process, including the materials and chemistry that are susceptible to hydrogen. Currently, most industry standards only require a test once every 90 days to determine the process’ susceptibility. We test ours every 30 days. We want to see that every variable and additive is always under our control.
Hydrogen has many places it can enter a bolt, and you cannot always be 100% sure that you have eliminated it. So in addition to our frequent testing and use of additives, we bake out hydrogen from our nuts and bolts for a minimum of eight hours to evaporate the hydrogen. These three processes allow us to be as certain as we can be that hydrogen has been eliminated and will not lead to embrittlement.
Calculating the K Factor
To perform its vital role, a fastener must be installed properly. To provide proper installation, the team that is on the front line of these critical turnaround maintenance operations must be given the right tools for the job. Any company can produce a coating that resists harsh environmental conditions, but if the coating can’t stand up to the work done on the fastener and isn’t consistent when it comes to calculating required torque, then the bolt is compromised from the start.
To calculate a fastener’s required torque, a turnaround team needs to know the diameter of the bolt, the amount of tension the bolt will need to hold the flanges together, and all of the factors that act on the bolt to resist these forces. These resistance factors are very difficult to calculate and to keep consistent from fastener to fastener, which is why consistency was one of our top priorities when looking for a coating solution.
Our coating process maintains a consistent low coefficient of friction which makes torquing easier overall, but this consistency also allows us to reliably calculate the resistance factors and put them into a number that we can provide to turnaround teams: the K factor.
T = K * db * Fp
We place our fasteners’ K Factor on the side of every box and the user guide that comes with the box, so the torque value can be calculated and applied with ease. A dent in a bolt’s thread can have a 30% effect on its torque value, so our packaging also prevents the rigors of shipping and storage from affecting the K factor and compromising the fasteners’ integrity. This helps turnaround teams remove the risk of overtorquing the bolts, which could lead to larger operational issues. It’s another way Doxsteel Fasteners were designed for the end user.
»Learn more about how our packaging helps turnaround teams.