The steel that makes up all Doxsteel Fasteners can only be used if our team is presented with each heat load’s Material Test Report, the steel mill’s thermocoupler certificate of calibration, and the results of the heat load’s processing. We then retest the heat load, generating our own in-house MTR to take responsibility for the fasteners. We test the heat load for its chemical composition, yield strength, tensile strength, percentage of elongation and reduction of area, and hardness. If the company passes our audit and the MTR meets our standards, we move forward with our process. We audit our suppliers once a year using API 20E specifications to make sure they meet our rigorous standards.
Once the heat load has been purchased, it is formed into nuts and bolts. All of our fasteners are roll threaded and comply with ASME specifications for unified inch screw heads. This helps us provide consistent threading to which we can apply our Nickel-Cobalt plating. Even in this stage, we take responsibility for the oils used during the rolling process, so when the time comes to clean the bolts for coating we know exactly how to prepare the substrate for application.
Cutting, Cleaning, & Coating
Next, the fasteners are cut to their required lengths and cleaned to eliminate contaminants. We do not sandblast; we use a chemical surface preparation to establish a clean substrate that is free of any contaminants that can compromise the integrity of the fasteners. This process is controlled, tested, and monitored throughout.
After cleaning, we coat our fasteners using a controlled electroplating process. Through electrolysis, we charge the bolts and attract the Nickel-Cobalt alloy, completely covering the entire part in a consistently thick protective coating.
Delivery & Assembly
Once the fasteners are ready to go, we package them in our durable, color-coded boxes. Our boxes are specially designed to withstand the rigors of shipping and storage in facility warehouses, and to mitigate human error in the warehouse and on-site. The parts are individually wrapped so they aren’t compromised during handling. Our boxes are easy to organize in your warehouse; they are stackable, and each color corresponds to a steel type. Different colored boxes contain bolts requiring different amounts of torque for installation, so you can be sure the right bolt is going to the right place.
When the time comes for installation, the box holds valuable information for the turnaround team, including the K Factor needed to calculate required torque, and the Doxsteel MTR. Any industry professional will tell you that every fastener on a flange needs to have a uniform load to prevent leaks. Using the correct K Factor is critical to ensuring an even load on each bolt.
Ongoing Quality Assurance & Testing
Once a fastener has been installed, we let it do its work. Each nut and bolt is marked with a number that traces back to its heat load and coating, so you can reference its origins and MTR at any time. Doxsteel may not be there in the field, but we’re with you in the lab. We monitor samples of every heat load over time using our in-house FELT test to assess its condition, and our ongoing work toward a better of way of bolting continues.
Unfortunately, no fastener lasts forever. So when the time finally comes for your next turnaround, our bolts make it easier than ever. Equipped with our ongoing data and testing, you are able to perform turnaround operations before the fasteners seize and avoid having to make the choice between lengthy operational shutdown and risky hot bolting conditions.