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If multiple discrete flaws are detected that are in close proximity to one another, alignment rules are used to determine whether the flaws should be treated as nonaligned or as coplanar. Alignment rules are defined in many fitness-for-service codes and standards in the world. However, the criteria of the alignment rules are different in these codes and standards. This paper introduces the current alignment rules and, in addition, interaction of stress intensity factors for nonaligned through-wall flaws was calculated by finite element analysis. Also, brittle fracture experiments were performed on carbon steel plates with two nonaligned flaws. From these calculations and experiments, authors studied the effect of stress intensity factor interaction on fracture behavior and proposed a new alignment rule ,for linear elastic fracture mechanics evaluation. [DOI: 10.1115/1.3152229]

Cutting tool temperature distribution was mapped using the infrared-charge-coupled device during maching of carbon steel SS2511 (~AISI 3115) and stainless steel AISI 316L under oblique cutting conditions with chip breaker geometry inserts. Results indicated that the temperature on the rake surface was not uniform. Local maximum temperature points are present on the tool face at difference locations, i.e., land, groove, backwall, and at the end of tool chip contact. Further investigation of the effect of cuting parameters on the tool temperature indicated that a suitable combination of cutting speed and feed resulted in a lower tool temperature for conditions of comparable material removal rate.

Corrosion of steel exposed to magnetic fields is reported. The relationship between corrosion patterns and magnetic-field gradients near the steel is discussed.

Ductile materials such as AISI1008 low carbon steel characteristically exhibit poor chip breaking in conventional machining practices. This paper presents an environmentally clean cryogenic machining process which improves the breakability of AISI1008 chips by lowering the chip temperature to its embrittlement temperature. In this study, the brittle-ductile transition temperature of AISI1008 was experimentally determined to be between -60 [degrees] C and -120 [degrees] C. The discussion is focused on whether the chip can reach the embrittlement temperature before it hits an obstacle. A finite element simulation predicted the chip temperatures under various cutting conditions. Liquid nitrogen (LN2) was used to prechill the workpiece cryogenically. The results from the cutting tests indicate a significant improvement in chip breakability for different feeds and speeds by using this cooling technique. However, the effectiveness of cryogenetically prechilling the workpiece was found to be heavily dependent on cutting speed.

An investigation of the quenching of 1080 carbon steel cylinders has been carried out to determine the validity of a quenching process model for carbon steels. The process model included a description of the austenite-pearlite and austenite-martensite transformations in carbon steels, temperature-dependent material properties, and an elastic-plastic stress analysis. The model was simulated using the finite element method (FEM). An experimental study of the quenching of 1080 steel cylinders in water and two types of polymeric quenchants has also been carried out. The temperatures at three points within the cylinder during quenching were measured using thermocouples. The hardness and residual stress distributions along a cross-section of the quenched cylinders were determined using a Rockwell hardness test and an X-ray diffraction technique, respectively. The temperature-time histories, residual stress, and hardness distributions predicted from the FEM simulation of the quenching model were found to be in good agreement with the corresponding measurements. The quenching process simulation described in the study appears to be a promising tool for the design of heat-treatment process parameters for carbon steels.

A study was conducted on the change of magnetic flux imaging pattern by tensile deformation in a carbon steel. A clear striped pattern was observed after the fine plastic strain was deformed between 0.2% and 1% before strain-hardening. Luders bands were also seen in the plate surface, at the corresponding locations of the striped patterns. Results prove that magnetic flux imaging is a nondestructive approach to detecting deformations in steel.

Continuous cooling curves of an extra-low carbon steel under three cooling rates were measured. The flow stress of the steel was determined in compression tests while the temperature was decreasing. The phase transformation temperatures were established from the cooling rate curve. The latent heat during phase transformation was computed. A new variable, related to the volume fraction of transformation, was defined. Experimental findings indicated that this variable may be described by a quadratic equation.

A circumferential notch changes the fracture mode of medium carbon steel breakaway couplings from ductile to brittle, without affecting the tempering condition. Notch strengthening is also seen in similar couplings with an increase in strength of 30%. Wrong heat treatment schedule of construction component can lead to tempered martensite or temper embrittlement which will have a deleterious effect on the final structure.

The distortion and residual stress behavior of carburized and quenched gear steels are studied to develop an accurate model of the various phase transformations inherent in material systems. Data commonly used in the finite element analysis of residual stress are compared with those obtained through experimental procedures. Results indicate that existing data cannot be relied upon in the accurate prediction of strains and stresses.

The effects of temperature and strin rate on the yield stress behavior of three low carbon steels are investigated through experimental procedures. Tests are carried out in a servo-hydraulic testing machine wherein carbon steels specimen having different chemical compositions are subjected to tensile loads at varying temperature levels. Results show that the specimens' yield stress exhibit high sensitivity at low temperature and high strain rate levels.

The impact properties of a laminated composite based on ultrahigh carbon steel and a Ni-Si-steel interleaf material were analyzed using a heat treatment technnique that eliminates carbon diffusion. The miscrostructures of the heated laminated composite specimen was studied using a metallographical approach and a scanning electron microscope. It was found that the notch-impact toughness of the interleaf material affected the ductile-brittle transition temperature of the laminated composite.

Photoacoustic gas-cell detection was used to investigate the frequency dependence of the photothermal signal from laser processed and regular stainless-steel and low carbon steel. The results showed that the method was an effective and reliable technique for the measurement of thermal diffusivity depth profiles of a layer extending from the surface into the bulk.

The erosion-corrosion metal wastage characteristics of 1018 plain carbon steel used in the heat exchangers of fluid bed combustors (FBC) are investigated. Tests were conducted to determine the erosivity of FBC bed material particles with different compositions, shapes, and sizes. Results show that when the particles do not shatter on impact, their erosivity is dependent on their shape. Increasing the ratio of SiO2 to CaO and CaCO3 increases metal wastage. A linear transition ratio on each side of the metal wastage was also observed.