Papers by Keyword: Hole Drilling

Abstract: The use of structural steel in the industry is increasing every day, and the study of stress state after welding has been shown to be of great importance. Nondestructive techniques become quite appropriate to be performed before and during the service component of welded, and thus ensure its integrity. The magnetic technique to be nondestructive, and easy to apply in the field, has potential to be an inspection tool for measuring residual stresses and other microstructural parameters. In this work it was possible to analyze the state of residual stresses through nondestructive techniques, Magnetic Barkhausen Noise and X-ray Diffraction, as well as the semi-destructive technique, high speed hole drilling method, and thereby determine the residual stresses in ASTM A36 steel plate welded by MAG (Metal Active Gas) process.

Abstract: Residual stress measurement techniques can be categorized as either relaxation or diffraction methods. Practitioners often advocate a particular category and sometimes a specific technique (hole drilling, contour, XRD, neutron, etc) based on their experience or capability rather than using the best technique for the particular application. This paper considers some of the implications from applying this “drunkard’s search” or “streetlight” approach by examining examples where the critical stress could be hidden from both relaxation and diffraction measurements. A better approach to planning residual stress measurements would begin with a detailed consideration of why the stresses should be measured and how the results will be used. Only then can the most appropriate measurement plan be developed. Since a single measurement technique cannot reveal the full state of stress, especially in challenging parts, the use of multiple measurement types often provides the most useful information to customers.

Abstract: Stress harps with bars of different size were used to study residual stresses due to different cooling rate during casting of a grey iron. Finite element (FE) simulations were performed to predict residual stresses from the casting process and the effect of a stress relieving heat treatment. Intended for validating the simulations, neutron diffraction (ND) and hole drilling methods were used to measure the residual stress distribution through the thickness and in a thin surface layer, respectively. Good agreement between the FE simulations and ND measurements is observed for the annealed harp and the normal and transverse directions of the as cast harp. Discrepancy occurs in the axial direction and especially in the side bars of the as cast harp for which the simulation shows much higher compressive residual stresses. The observed difference between the different techniques was discussed with respect to the characteristics of the different methods.

Abstract: This paper investigates residual stress due to fillet rolling on bolts made of ATI 718Plus® superalloy. Incremental hole drilling, neutron diffraction and neutron transmission have been used to assess residual stress near the bolt head fillet. A compressive residual stress field was identified in the first 0.5 mm from the surface. Post fillet rolling solution anneal can relieve the residual stress at the fillet.

Abstract: The hole drilling technique is probably the most widely used residual stress measurement technique. The ASTM E837 standard covers hole drilling measurements for thin and thick specimens. VEQTER have encountered several cases when the specimen was between the thick and thin specification. In order to gain a greater understanding of the sensitivity of the analyses and accurately measure the residual stresses using the hole drilling technique within intermediate thickness specimens and within thin specimens containing non-uniform residual stresses a study was performed.

Abstract: The abstract should be written after the paper is finished; it should state briefly the research problem, research methods and research results. The abstract length will not exceed 250 words. This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text. Please make the page settings of your word /left margins must be 2 cm (0.78 in). % by the publisher. Please keep this in mind when designing your figures and tables etc.

Abstract: The paper is devoted to the mathematical modelling and optimal control of hole drilling. Drilling feed is considered as control action while the cutting force is controlled variable. Transfer functions of the regulators were obtained, with the cutting force variance being used as quality criterion for the automatic control system. In the article has been presented also, questions connected with the structure of typical automated process projecting of the hole drilling operation. The block pattern of the typical process automated projecting was introduced. The processed algorithms of setting of the parameters of regulators according to a priori technological information and program protection were also introduced, to automate letting the process of the study of the automatic control system for the operation of the hole drilling.

Abstract: Coal bed Methane(CBM) is commonly known as “gas”，of which the main component is methane. It mainly exists in the coal seam in the adsorption state, not only different from petroleum which is also fluid but in the liquid state, but also different from the conventional natural gas which exists in the formation in the free state. In the present, the drilling technique of coal bed methane is mainly based on the drilling technique of petroleum. But as the coal bed methane is attached to the coal seam and different from the conventional hydrocarbon reservoir in the physical and mechanical properties and in the storage, it determines the particularity of the drilling techniques. This paper mainly discusses the drilling technique of coal-bed methane in order to provide some useful reference. Coal bed methane is an important type of non-conventional natural gas which has great potential for exploration.

Abstract: Dissimilar metal joints between pipes of ferritic and austenitic steels are present in primary coolant circuit of pressurized water reactors. Over the last years in particular in USA and Japan, stress corrosion cracks, often associated with weld repairs, have been observed for some dissimilar welds made with an Inconel filler metal. The integrity of this type of components is thus a major safety issue. In this context, the goal of this work is to evaluate the welding residual stresses field for a dissimilar weld joint. A representative bi-metallic tubular weld joint was fabricated and residual stresses profiles in the different weld zones were evaluated by means of the hole drilling and neutron diffraction methods.

Abstract: Measuring residual stress at the sub-micron scale imposes experimental challenges. We propose a new technique, namely the incremental micro-hole-drilling method (IµHM), for measurement of residual stress profiles as a function of depth with high spatial definition. Like its macroscale counterpart, it is applicable to either crystalline or amorphous materials, but at the sub-micron scale. Our method involves micro-hole milling using the focused ion beam of a dual beam FEGSEM/FIB microscope. The surface displacements are tracked by digital image correlation of SEM images recorded during milling. The displacement fields mapped around the whole are used to reconstruct the variation of the in-plane stress tensor as a function of depth. In this way the multi-axial state of residual stress has been characterised around drilled holes of 2 microns or so, enabling the profiling of the stress variation at the sub-micron scale to a depth of 2 microns. Here we demonstrate the efficacy of this method by measuring the stresses in a surface-severe-plastically-deformed (S2PD) Zr50Cu40Al10 bulk metallic glass (in atomic percent, at.%) sample after failure under four-point-bending-fatigue.