Burst Pressure Prediction of Small Diameter Thin-Wall Steel Pipes

Literature Overview

This paper by Xu Yan, Liu Yinglai, Nie Xianghui, Feng Zhenjun, Wang Gaofeng, and Li Liang (2017, Oil and Gas Storage and Transportation, Vol. 36, No. 11, pp. 1265-1269) addresses the critical engineering problem of accurately predicting the burst pressure of small diameter thin-wall steel pipes used in oil and gas pipeline systems. The research was conducted by the Petroleum Pipe Engineering Technology Research Institute of China National Petroleum Corporation and Beijing Longsheng Taike Petroleum Pipe Technology Co., Ltd. Accurate burst pressure prediction is essential for pipeline system design, integrity assessment, and operational efficiency improvement.

Experimental Program and Methodology

Static hydrostatic burst tests were conducted on commonly used small diameter thin-wall steel pipes in oil and gas pipelines. Multiple prediction formulas and methods were compared, and deviation analysis was used to evaluate the accuracy of predicted results against experimental measurements.

Prediction Formulas Evaluated

Formula	Basis	Applicability
ASME formula	Code-based	General purpose
Barlow OD formula	Outside diameter based	Thin-wall approximation
Barlow ID formula	Inside diameter based	Thin-wall approximation
Maximum shear stress formula	Tresca yield criterion	Thin-wall pipes
Turner formula	Empirical correction	Small diameter pipes

Core Technical Findings

Yield Criterion Comparison

The most significant finding is that the Tresca (maximum shear stress) yield criterion provides burst pressure predictions closer to actual experimental results compared to the Von Mises yield criterion. This result has important theoretical implications:

The Tresca criterion's maximum shear stress plastic failure mode more readily explains the hydrostatic burst process of small diameter thin-wall steel pipes.
In thin-wall tubes under internal pressure, the stress state is dominated by hoop stress, and the maximum shear stress occurs on planes at 45 degrees to the principal stress directions.
The Tresca criterion is more conservative than Von Mises for this specific loading condition, which provides a safety margin in design.

Formula Applicability

All five evaluated formulas (ASME, Barlow OD, Barlow ID, Maximum shear stress, and Turner) demonstrate enhanced applicability when considering the geometric characteristics of small diameter thin-wall steel pipes. The Turner formula, which incorporates empirical corrections for small diameter effects, generally provides the most accurate predictions.

Geometric Effects

For small diameter thin-wall pipes, the following geometric effects become significant:

The ratio of wall thickness to diameter affects the stress distribution through the wall thickness.
Manufacturing tolerances have a proportionally larger impact on burst pressure for small diameter pipes.
Residual stresses from cold forming processes influence the actual burst pressure.

Engineering Practice Implications

Pipeline Design and Integrity Assessment

Application	Recommended Approach
Design pressure calculation	Use Tresca-based formulas for conservative estimates
Integrity assessment	Compare multiple formulas; use Turner formula for small diameter pipes
Safety factor selection	Account for manufacturing variability in small diameter pipes
Failure mode analysis	Consider maximum shear stress failure mechanism

Quality Control Requirements

For manufacturing small diameter thin-wall steel pipes intended for pressure service:

Wall thickness uniformity must be tightly controlled (typically within ±10% of nominal thickness per API 5L or GB/T 9711).
Hydrostatic testing during production should use pressures calculated with Tresca-based formulas to ensure adequate safety margins.
Surface defects (scratches, dents, inclusions) should be minimized as they act as stress concentrators that reduce burst pressure below theoretical predictions.
Heat treatment and residual stress relief should be considered for critical applications.

Study Insights and Reflections

This research provides valuable practical guidance for pipeline engineers working with small diameter thin-wall steel pipes, which are increasingly used in modern oil and gas systems for their weight efficiency and cost-effectiveness. The finding that the Tresca criterion outperforms Von Mises for this specific application is notable, as the Von Mises criterion is generally considered more accurate for ductile materials under complex stress states.

The explanation that maximum shear stress failure more readily describes the burst process of thin-wall pipes is physically intuitive. In a thin-walled cylinder under internal pressure, the hoop stress is the dominant stress component, and the maximum shear stress acts on planes oriented at 45 degrees to the pipe axis. This orientation corresponds to the characteristic helical crack pattern observed in burst pipe failures.

For pipeline integrity management, the comparison of multiple prediction formulas allows engineers to establish confidence intervals for burst pressure predictions. The Turner formula, with its empirical corrections for small diameter effects, should be considered the preferred method for small diameter thin-wall pipe applications, while the Tresca-based maximum shear stress formula provides a physically justified theoretical alternative.

The practical significance of this research extends beyond design calculations to operational decision-making, including determining maximum allowable operating pressures, evaluating remaining life of in-service pipes, and establishing safety factors for pipeline systems operating under varying pressure conditions.