Manufacturing HDD drill pipe is serious business, and Premier Drill Products brings serious machinery, knowledge, and processes to an industry which demands serious attention to detail. We give our HDD drill pipe the same attention to detail and manufacturing quality controls as we give our oilfield drill pipe. Just because the pipe is smaller, doesn’t mean the job is less important. Walk through our manufacturing process below, or click here to see an infographic which briefly outlines the steps described on this page.
We start with a specialized chemistry carbon alloy tube body. Our 4130 Carbon alloy green tube starts its journey by transiting a slot furnace to be heated to 2,300 degrees. Once at the required temperature, the end is secured in a set of precision machined dies. The forge’s center punch pushes the 2,300-degree steel into the die recess to make the forged upset. After the upset is complete, the forging is inspected internally and externally, and then ground on the edges where steel flashed between the dies.
How we save you money
At Premier Drill Products we forge all our HDD drill pipe. Other manufacturers depend on outside vendors to supply their one-piece forgings. Paying a vendor, means paying someone else’s margins. Premier doesn’t have to pass those costs to you.
After the forging process, the forged drill rods are then sent through a series of induction coils and a gas furnace for Austenitizing where the pipe is heated to 1650 degrees. Immediately upon exiting the Austenitizing furnace, the pipe is quenched with a polymer based fluid to set the final microstructure, which makes the steel very hard. At this point the steel is too hard for use on an HDD rig, as it would crack due to how brittle it is. Thus, the pipe is sent straight to a tempering furnace where it is again heated. This time, however, it is only brought up to around 1000 degrees. This step takes the sharp grain structure of the steel and relaxes it enough so it is now both hard and durable.
The steel is heat treated to S135 grade, which means it has 135,000 lbs. of tensile strength per square inch. Some drill pipe on the market is heat treated to only P110, which is 110,000 lbs. of tensile. Having a higher tensile strength means the pipe can resist bending and rotational fatigue longer.
Heat treating is a very specialized process, and if done incorrectly can have catastrophic results. Tejas Tubular (our sister oilfield tubing company) heat treats our tube bodies. Tejas processes over 200,000 tons a year… heat treating pipe right the first time is something we do everyday!
How we save you money
At Premier Drill Products we can process all our HDD drill pipe from start to finish. Other manufacturers depend on outside vendors to supply Heat Treatment. Not only does paying a vendor result in costs that are passed on to you… quality control cannot be monitored as vigorously.
The furnace exerts a tremendous amount of energy on the green tube, and the unfortunate result is pipe that isn’t perfectly straight. Thus, after coming out of the temper furnace, the pipe enters a cross-roll and gag straightener where it is put back into alignment. Once the pipe is straightened and passes it’s QC checks, it is sent to the next part of the process or into storage for upcoming orders.
Weld Prep: “Turn and Face”
In order to get the best, and most consistent, weld on the inertia welder, the forged tubes need to have their outside diameters turned down and their weld surfaces machined (facing). This ensures that the weld area on each part being fused is equal in diameter and, that the faces are bonding uniformly during the inertia weld process.
Tool joints are threaded Simultaneous to the turn and face operation, in our machine shop. Our tool joints are machined by veteran machinists with an eye for detail and a penchant for efficient manufacturing.
Once each tool joint is completed, it is inspected using the JSS measuring system from Gagemaker. Aside from providing the normal measurements typically used to qualify a tool joint as “prime”, JSS can measure the tool joint’s pitch diameter. Pitch diameter is a crucial measurement which cannot be accomplished using the old industry standard ring-&-plug gauge. Pitch indicates how the threads are engaging with each other as the pin and box threads are torqued together. Better engagement means better tools, better tools means less time worrying about your drill pipe as you send it out to do the one job is was made to do.. At Premier Drill Products, we dedicate a lot of time and engineering making sure our drill pipe is the best option you have available to you.
The “welding” part of inertia welding often causes some confusion. The tool joints and the forged tube bodies are in-fact being welded to each other, but not in the way the word “welding” is typically used. In this process, the Inertia Welder uses a weighted spindle to hold the tool joint. This spindle is then spun to a very specific RPM. Once the appropriate RPM is reached, the drive motors disengage and the spindle is allowed to free-spin through the inertia gained as a result of the added weight. The tool joint and forged tube body are then pressed together at controlled pressures until the spindle stops spinning. The force exerted by that pressure & rotational mass creates heat, enough heat to turn the carbon alloy steel to a plastic state. It’s this plastic state which allows the two (previously separate) pieces to fuse together into one solid piece. Interestingly, this process can be used to weld together dissimilar metals, like bronze to aluminum, or titanium to brass
How we save you money
At Premier Drill Products, we don’t have to pass on certain costs to the customer, case in point: if for some reason a drill rod is found to be defective, it’s not wasted. Instead, we can cut off the tool joint and re-weld the non-defective part. Or, the defective piece can simply be used for our and tensile quality check.
One piece forged rods cannot be salvaged once they’ve been threaded.
The heat produced during the inertia weld changed the grain structure of the S135 heat treated steel at the weld zone. To bring the tool joint and tube body’s weld zone back into S135 hardness and tensile range, the weld zone is placed in an induction coil where it is re-tempered.
Once the post-weld temper is complete and the outside diameter cleaned up, the final inspection can commence. First, angular and parallel alignment of the tool joint to the tube body is checked to ensure the weld was successful and meets tolerances, then the mechanical properties of the tube body are checked against a specification set forth by the American Petroleum Institute (API).
Once the previous quality checks are complete, the tube is briefly magnetized and bathed in a fluid containing suspended metallic particles. If a crack or inclusion is present from the weld process, the metallic indicators are attracted to the defect, and plainly show the inspector the previously invisible fault. Once all the standards are met, we spray a protective coating on the pipe and it’s ready for you to put it to work.
Why do we go through all this trouble?
Unlike one piece forged rods… there is an actual API standard for inertia welding tubes and tool joints together. All oilfield drill pipe is inertia welded, just go ask a Maxi Rig operator how his pipe was made. (hint: it’s inertia welded, and probably also oilfield drill pipe)
It is precisely the reason why oil field drill pipe is inertia welded that we use the same process for HDD.
So why do we go through all this trouble? Simple. If we’re going to put our name on it, then it’s going to be the best!