Quality Control

In a perfect world, every fabrication project starts with a clean, accurate drawing. In reality, that’s not always the case. Equipment has been modified over time, documentation is outdated, or drawings simply no longer exist. When that happens, fabrication doesn’t stop, it just requires a different approach.

At Abtrex, we regularly see situations where a pipe must be rebuilt or replaced, but the only reference available is the pipe itself. No dimensions to rely on, no verified layouts to trust. Just an existing installation that still needs to function when the job is done.

Step One: Starting With What’s Actually There

When a proper drawing is missing, the first step is understanding the physical reality of the pipe as it exists today, not how it was originally designed. Over years of operation, piping systems can shift, sag, or move out of alignment. Flanges, nozzles, and tie‑ins may be added or modified in the field. Assuming original geometry in these situations increases the risk of dimensional errors and fit‑up issues during fabrication.

Instead of forcing outdated information to work, the focus shifts to capturing real-world geometry and translating it into something that can be fabricated on a shop floor.

Many of these pipes are installed high above the floor or tucked into tight spaces, making accurate measurements with tape alone impractical. To address this, Abtrex works with Wadelynn Geospatial to capture high-resolution 360-degree imagery and 3D laser scans of the installed piping systems. These scans capture not only visual detail but also precise spatial data, creating a complete digital record of the pipe as it exists in place. Connections, nozzle locations, and surrounding interferences are all documented in context, providing a far more accurate reference than standard photography.

Step Two: 3D Scan to CAD

The collected scan data forms a unified 3D point cloud of the piping system. Using LiDAR-based scanning technology, this digital model represents the exact geometry and spatial relationships of the installation in measurable form. It allows our engineers to rotate, zoom, and inspect every section from any angle, supporting accurate understanding of existing conditions without needing to physically access every location. To further assist in the creation of a workable 3D model for fabrication, Wadelynn engineers can convert the point cloud into a rudimentary solid model in a variety of CAD formats.

While the scan provides critical dimensional insight, it’s not treated as a perfect blueprint. Measurement detail is selectively intensified in key areas, based on access and available lines of sight, to capture precise dimensions essential for fit-up and performance. Certain measurements may fall between standard pipe sizes, especially when the original installation has shifted or sagged over time. Recognizing those limitations is part of the process.

Step Three: Where Experience Kicks In

An Abtrex engineer reviews the scan data and begins validating it against known piping standards and expected component geometries. When a measurement doesn’t align with known pipe standards, it’s flagged and checked against other reference points.

For example, flanges are typically standardized components, so their dimensions provide a reliable reference point. When a flange does not match expected ANSI standard sizing, it indicates that the system may include non-standard or internationally sourced components. The scan data helps identify and document these differences, so the final design accurately reflects what is physically installed, rather than assuming uniform standardization.

Step Four: Building the Actual Model

When the geometry is verified, the pipe is modeled in SolidWorks. The final SolidWorks model becomes the foundation for pipe fabrication, translating visual data and engineering judgment into something that can be built on the production floor, including a bill of materials. This approach allows Abtrex to produce a custom pipe that fits the system while still meeting fabrication and installation requirements.

By the end of the modeling phase, the pipe is fully defined and ready for fabrication. What started without a drawing is converted into a verified pipe spool based on confirmed dimensions and standardized geometry.

When a drawing doesn’t exist, Abtrex doesn’t guess. We build the path from the field to the model, and from the model to a finished custom pipe.

In tank fabrication, surface preparation is one of those steps that quietly determines whether a coating system succeeds or fails. Invisible contaminants on the metal surface can undermine the entire structure. Soluble salts, particularly aggressive chloride ions, are infamous for causing premature coating failure and aggressive corrosion.

Chloride tests pinpoint the exact ions responsible for rapid steel degradation. Understanding how to find and eliminate these ions is essential for building durable industrial equipment.

The Impact of Chlorides on Storage Tanks

Chloride contamination is often invisible. A steel tank can look clean, meet visual standards, and still carry enough salts to trigger premature coating breakdown. Even after abrasive blasting, chloride ions can remain trapped in the microscopic pits of carbon or stainless steel. Once trapped beneath a lining or coating, chlorides attract moisture, leading to blistering, osmotic effects, and ultimately corrosion. For tank fabricators this is a risk that can’t be ignored.

Why Chloride Testing Is Used

In modern custom tank fabrication, chloride testing is often part of quality control before lining and/or coating application. It helps verify that the surface meets project specifications and reduces the chance of corrosion barrier failure later in service. For clients investing in long-term performance, this step is just as critical as the coating itself.

Chloride testing is particularly important in environments where tanks are exposed to marine air, salts, or other process contaminants.

How to Perform a Chloride Test

Field testing for chlorides is straightforward when using a dedicated extraction kit. Unlike automated conductivity meters, the chloride test specifically isolates and measures chloride ion concentrations. Here is a step-by-step guide to conducting the test:

1. Prepare the Extraction Sleeve
   Take the specialized latex sleeve and pour the provided proprietary extraction liquid inside. This fluid is formulated to lift salts from the metal effectively.
2. Attach to the Surface
   Peel the protective backing off the adhesive collar on the sleeve. Press it firmly against the steel surface. Massage the edges to ensure a watertight seal so no liquid escapes.
3. Extract the Contaminants
   Massage the liquid against the metal for two to three minutes. This physical action pulls the aggressive chloride ions out of the steel’s pores and suspends them in the solution.
4. Perform the Titration
   Remove the sleeve carefully to retain the liquid inside. Snap off both ends of the glass titration tube and insert the bottom end into the extracted solution. The liquid will slowly wick up the tube. It will change color based on the exact concentration of chlorides present in the liquid.

Interpreting Results and Mitigation Strategies

Reading the results is as simple as checking the color change on the titration tube’s printed scale. The reading typically displays the concentration in parts per million (ppm) or micrograms per square centimeter.

If the test reveals chloride levels above the specified project limits, you must take immediate mitigation steps. Standard dry abrasive blasting will not remove these salts. Instead, tank fabrication teams use specialized chemical wash solutions or high-pressure water jetting mixed with soluble salt removers.

After washing and thoroughly drying the surface, perform another chloride test. You must verify the surface is completely clean before proceeding with any coating application.

Why Choose Abtrex for Your Custom Tank Fabrication

Failing to detect chloride contamination is a costly mistake. By implementing rigorous testing protocols, you protect your assets from hidden corrosion and extend their operational lifespan. Ensure your team integrates the chloride test into their standard quality assurance checklist before applying any primers or coatings.

As experienced custom tank fabricators, we take pride in delivering high quality, corrosion-resistant storage tanks tailored to your specifications. When you choose our team, you benefit from a commitment to rigorous surface preparation, thorough chloride testing, and expert craftsmanship at every stage. Contact us today to discuss your next custom tank fabrication project and see how we can help you achieve long-lasting, reliable results.

Producing large industrial vessels requires precision, structural integrity, and highly controlled manufacturing processes. To meet these stringent demands, our production facility relies on advanced automated welding technology. By minimizing the variability associated with manual welding on large-scale projects, we ensure that every seam meets rigorous industry standards.

A key element of this capability is our automated submerged arc welding (SAW) machine. As a central part of our heavy fabrication operations, it enables consistent, high-quality welds on demanding industrial projects. Understanding how this system operates provides insight into the methods we use to support the long-term performance and safety of the vessels we manufacture.

Technical Capabilities of our SAW System

Submerged arc welding is a process where the welding arc is buried beneath a layer of granular flux. This flux shields the molten weld pool from atmospheric contamination, eliminating the need for shielding gas and preventing hazardous sparks or spatter. While the fundamental chemistry of the process is impressive, the true power of our SAW system lies in its automation.

Our SAW machine is fully integrated with a heavy-duty gantry and a set of synchronized turning rollers. When working on a cylindrical structure, the rollers rotate the piece at a precise, programmed speed. Simultaneously, the gantry positions the welding head with pinpoint accuracy. This automated synchronization allows the machine to perform continuous weld passes along extensive joints without manual intervention.

 

Driving Efficiency and Repeatable Quality

The primary advantage of our automated SAW system is its capacity to run larger diameter wire compared to standard semi-automatic welding processes. This capability translates to exceptional deposition rates, allowing us to lay down large volumes of weld metal rapidly and efficiently.

Because the system operates on a continuous rotation using the gantry and rollers, it reduces the number of starts and stops required during a weld. Every start and stop in a traditional welding process introduces a potential weak point or defect in the joint such as a cold lap at a stop or incomplete fusion at a restart. By maintaining a continuous pass, our SAW machine eliminates these vulnerabilities.

Within our fabrication sequence, shell sections are fitted to heads while maintaining a controlled weld gap. Root passes are completed manually by ASME-certified welders, after which the longitudinal and circumferential cover passes are welded using the sub arc system. This combination of skilled manual execution and mechanized welding ensures optimal joint performance.

Mechanized control of travel speed, voltage, and wire feed enables consistent penetration along the full weld length, resulting in repeatable weld quality and uniform metallurgical properties throughout the joint that manual processes simply cannot match.

Applications in Heavy Plate and Tank Fabrication

The high deposition rates and deep penetration of the SAW process make it well-suited for heavy plate applications. When constructing a pressure-retaining tank vessel, the integrity of full penetration metal joints is non-negotiable, regardless of thickness.

Our automated SAW system is specifically optimized for high-capacity tank fabrication. Whether we are rolling and welding thick carbon steel for chemical processing or utilizing high-grade stainless steel to prevent corrosion in food and beverage applications, the SAW process easily accommodates the heavy materials required. The system flawlessly handles the longitudinal seams and circumferential welds necessary to assemble large storage tanks, ensuring that the structures remain leak-proof and structurally sound under extreme pressure.

Partner With Us for Your Next Manufacturing Project

The integration of automated submerged arc welding is just one example of our commitment to advanced fabrication practices. By investing in process control and automation, we reduce production times, minimize the margin for error, and deliver a final product engineered for decades of reliable performance.

If your next project requires robust engineering and flawless execution, our team is equipped to deliver. Contact us to discuss how our custom fabrication services can help bring your heavy plate and storage tank designs into operation.

When rubber-lined equipment is specified for an application, it is typically driven by performance requirements such as chemical resistance, durability, and long-term protection of critical assets. Rubber linings are widely used in storage tanks and industrial vessels applications where high performance under specific service conditions is required. While these materials are engineered for demanding environments, their integrity and service life are strongly influenced by how the equipment is stored when it is not in operation, particularly when exposed to cold ambient temperatures.

Material behavior at low temperatures

Cold temperatures reduce molecular mobility in all elastomers, including cured natural rubber and other rubber lining materials. As temperatures decrease, rubber linings exhibit increased stiffness, higher apparent hardness, reduced flexibility, and lower impact resistance. These effects are temporary in nature but can become problematic when combined with mechanical stress, handling, or rapid temperature changes.

Cured rubber also exhibits a higher coefficient of thermal contraction than steel or other common substrates. During cold exposure, this differential shrinkage can introduce tensile stresses within the lining and at the bond interface. In hard and semi-hard linings, which are less tolerant of strain, these stresses may increase the risk of cracking, adhesion loss, edge lifting, or localized debonding, particularly under vibration or impact.

Many hard and semi-hard rubber compounds are not recommended for exposure below freezing temperatures. Some formulations may require controlled shipping, storage, or handling below approximately 32°F, with additional precautions below 20°F. Manufacturer specific compound limitations should always be reviewed when establishing storage protocols.

Storage location versus temperature exposure

Cold-weather considerations apply wherever rubber-lined equipment is exposed to low or fluctuating temperatures. Equipment stored outdoors, in unheated warehouses, or in buildings without climate control may experience similar thermal conditions. From a technical standpoint, the response of the rubber lining is governed by temperature and thermal cycling rather than physical location.

When a rubber-lined tank that has been stored at low temperature is returned to service, introducing warm or hot process media can subject the lining to thermal shock. Rapid temperature changes may intensify stress within the lining system, particularly in areas of geometric complexity or minor surface irregularities. Features that are benign under stable ambient conditions may become stress concentrators during rapid heating.

To mitigate these risks, manufacturers consistently recommend minimizing sudden temperature changes and allowing equipment to equilibrate gradually before handling or placing it back into service.

Recommended storage and protective measures

Manufacturers of rubber linings generally provide similar guidance for cold-weather and long-term storage:

• Store rubber-lined vessels away from direct sunlight, ozone-generating equipment, and environments subject to rapid temperature fluctuations.
• Protect outdoor-stored tanks with suitable poly covers or tarpaulins to reduce exposure to wind, precipitation, and rapid cooling.
• Hard and semi-hard rubber-lined equipment should be stored indoors whenever feasible and protected from cold climatic conditions.
• Idle or standby rubber-lined tanks may benefit from protective measures such as a nitrogen purge or partial filling with a non-freezing solution, provided the liquid is not allowed to freeze.
• In certain cases, surface protection using a silicone emulsion may be recommended to reduce environmental degradation during extended storage periods.

After exposure to cold storage, a detailed inspection should be conducted prior to returning the equipment to service. Inspection should focus on cracks, edge debonding, localized hard spots, and other indications of cold-related stress or loss of adhesion.

Installation and mechanical considerations

Cold-weather exposure also affects auxiliary components associated with rubber-lined equipment. Gasket selection and bolting practices are particularly important. A commonly recommended approach is to use gaskets that are approximately 10 durometer points softer than the rubber lining itself. This helps ensure adequate sealing while minimizing localized stress concentrations at flanges.

Bolt torque values and patterns should be carefully controlled and verified, especially after cold storage, to account for material stiffness changes and differential thermal contraction. Improper torque can exacerbate stress at the lining interface and reduce long-term reliability.

Preserving lining performance

Rubber linings remain a high-quality, high-performance solution for chemical service and corrosion protection when handled in accordance with manufacturer recommendations. Proper storage practices, controlled temperature transitions, and thorough inspection prior to service are essential to maintaining the intended service life of a rubber-lined tank.

By treating storage conditions as an extension of the overall service environment, operators can ensure that rubber-lined equipment continues to perform as designed- through seasonal temperature changes and throughout its operational lifecycle.

When a coating industry customer sent an initial “sketch-level” concept for large stainless-steel tanks, our engineering team transformed the idea into a validated, build-ready design. The application involved sulfuric acid, a strong highly corrosive mineral acid with powerful dehydrating and oxidizing properties, and significant structural loads, making robust engineering essential.

Why Finite Element Analysis (FEA) Matters

The largest of the five open-top tanks measures 312″ L x 84″ W x 84″ D with a 9,500-gallon capacity.  The other four are 12” narrower.  The ¼” thick shells, top rim and nozzles  are all grade 316 stainless steel, and structural steel supports are 304 stainless steel. Filled with sulfuric acid (≈1.83 g/cm³), the hydrostatic pressure and a ~20,000-lb rim load demanded more than rule-of-thumb design. Abtrex design engineers used Finite Element Analysis (FEA) to simulate combined fluid, gravity, and rim loads and visualize stress and deflection throughout the structure.

FEA breaks a structure into small elements, applies loads and constraints, and calculates stress and deflection. This process allowed our team to identify overstressed regions and optimize the beam layout for safety and cost efficiency.

Design Study Results

The initial concept used six longitudinal beams, but FEA revealed excessive mid-span stress and deflection. Under combined hydrostatic pressure (increasing toward the floor) and the applied ~20,000‑lb rim load, color maps showed critical zones forming near the center while displacement plots indicated the top mid‑span bowing nearly an inch in the early iterations.

To correct this, our engineers added a central beam and redistributed supports inward from the corners, where members had behaved more like “table legs” than effective structural stiffeners, then iterated beam positions until the stress field became uniform. Animated load cases (fluid head + rim load, with floor constraints) confirmed the progression from low stress (blue) to acceptable operating levels (green) as the optimized layout engaged. The final configuration reduced peak stress to ~19,000 psi, well below the 30,000 psi yield strength, and limited deflection to 0.3 inches, even assuming a completely full tank. This optimization was crucial because stainless steel is significantly more expensive than mild steel, making material efficiency a priority.

Corrosion Protection

One of the five tanks receives a rubber lining to provide a protective layer against corrosive elements. Abtrex applies a ¼-inch bromobutyl rubber lining after abrasive blasting the metal surface to achieve a 2‑mil angular anchor profile. This process ensures proper adhesion and delivers long-term performance under high abrasion and chemical exposure. The added protection complements the stainless-steel construction, extending service life under harsh chemical and environmental conditions.

Every tank undergoes dimensional verification, 100% visual weld inspection by our in-house certified welding inspector (CWI), and liquid dye penetrant testing of shell welds. These steps, combined with Abtrex’s expertise in rubber linings, fabrication, and corrosion resistant solutions, ensure long-term reliability under a wide range of environmental conditions.

If you are ready to optimize your next project, contact the Abtrex engineering team to discuss custom-engineered solutions for stainless steel tanks, corrosion protection, and advanced design services.