Product Attributes - PVC and CPVC Bar, Rod, Tubing & Angle Stock

PVC Solid Round Internal Stress Comparison

Inherent Stress
Laboratory tests show GF Harvel PVC solid
rod outperforms other brands with
significantly lower inherent stress levels.

More than 45 years of processing experience has enabled GF Harvel to refine the art of extruding machining shapes into an exacting science. This experience has made it possible to customize dedicated production equipment, addressing specific extrusion requirements.

Every aspect of the process, from raw material traceability through online testing, is continually monitored, and finalized with formal quality-control testing of finished product. Rigorous in-house TQM/SPC requirements and tough self-taught standards ensure consistency in product quality from start to finish. Key processing techniques that contribute to final product properties are carefully balanced during production to provide optimum quality.

In addition to maintaining tight dimensional tolerances, emphasis is placed on processing conditions that effect end product properties, performance, and overall quality. Focusing on and balancing the following quality requirements maximize product performance.

Degree of Fusion
Proper fusion of materials during the manufacturing process optimizes physical properties such as tensile strength, tensile modulus, flexural strength, impact resistance and other important properties that contribute to end product quality.

In addition, end-product performance in aggressive environments is dependent on the compatibility of the material selected with chemicals used during service. The degree of fusion and consistency of the melt during the manufacturing process greatly affects chemical compatibility. Product that is not properly fused during the extrusion process can result in substandard components with poor chemical resistance. This issue is addressed at GF Harvel with online and formal Q.C. tests to measure the degree of fusion throughout the entire product profile.

Porosity and material contamination issues can create costly scrap and downtime when working with machine stock. GF Harvel uses only the finest raw materials and narrow, well-defined processing conditions for each type of product manufactured. This greatly reduces risks associated with material contamination related to substandard compound, and porosity caused by poor processing techniques.

Dimensional Stability
GF Harvel has painstakingly developed methods without secondary annealing processes to reduce and monitor internal stress levels, addressing the dimensional stability characteristics of finished product when subjected to machining procedures. Residual stresses are inherent in all extruded profiles due to the nature of the extrusion process. The amount of inherent stress will affect the product’s long-term stability, toughness, and machining characteristics. Stress created by the manufacturing process of GF Harvel profiles is minimized to ensure consistent machine stock with excellent dimensional stability.

Low inherent stress levels reduce the potential for fatigue and stress fracturing when products are subjected to heat cycling and various other physical demands caused by machining. Optimal product quality is achieved by producing machining shapes that can consistently withstand the vigorous demands and intricacies of complicated machining practices.

Camber and Bow
In addition to maintaining exacting tolerances on outside diameters, care is taken to ensure straightness of GF Harvel extruded products. Keeping close tolerances on camber and bow is second nature on all GF Harvel products. This enables successful machining of specialty products where overall length of a finished part is critical.

Each finished product produced by GF Harvel is stamped and identified for tracking purposes. Careful handling, packaging and storage ensure quality is maintained from door to door.