Testing method for accelerating evaluation of slow crack increase resistance of polyethylene tube

Abstract

The invention relates to a testing method for accelerating evaluation of slow crack increase resistance of a polyethylene tube. The testing method comprises the following two steps: preparing a testing sample, and performing high-temperature tension testing, wherein the testing sample is prepared through procedures of compression molding, annealing and stamping. A relationship curve of stress and strain is obtained through the high-temperature tension testing on the testing sample, a slope of the testing sample is calculated within a strain hardening interval that the stress is suddenly increased on t he relationship curve, then a strain hardening modulus is obtained for representing the slow crack increase resistance of a polyethylene material, and the larger the strain hardening modulus is, the better the slow crack increase resistance is. The testing method provided by the invention has the advantages of short time consumption, low material consumption, simple testing sample preparation step, good result reproducibility and the like.

Description

technical field [0001] The invention relates to a test method for evaluating the slow crack growth resistance of polyethylene pipes, in particular to a test method for evaluating the slow crack growth resistance of polyethylene pipes based on strain hardening response acceleration. Background technique [0002] Polyethylene (PE) pipes have the characteristics of good corrosion resistance, toughness, good flexibility, aging resistance, easy construction and installation, and have been widely used in gas, water supply and drainage, agricultural irrigation and other fields. However, PE pipes are prone to slow crack growth (Slow Crack Growth) during use due to incorrect welding or damage caused by production, transportation and construction, or even mechanical connection deformation. Under the condition of axial stress, the failure phenomenon occurs for a long time, so that the failure leakage occurs under the long-term internal pressure and affects the service life. Therefore, ...

AI Technical Summary

Problems solved by technology

However, this type of test method has the following disadvantages: (1) For commonly used PE100 pipes, the test time of this type of method is usually more than 1000 hours, while for PE100RC, the test time is basically more than 1 year, and the test cycle is lengthy; The test method needs to prefabricate the sample and prepare a suitable surfactant. The test steps are complicated, and more PE raw materials are consumed when preparing the sample; the accuracy of

These shortcomings affect the correct evaluation of the slow crack growth resistance of the pipe and also hinder the development speed of the pipe

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