A quantitative calibrated methodology based on photothermal radiometric (PTR) depth-profilometry for non-contact, non-intrusive determination of effective case depth in heat-treated case-hardened steel products was developed. Several types of heat-treated C1018 industrial steel screw products (with hexagonal, cylindrical and spherical heads) are statistically evaluated using the case-depth-indu...

This paper describes an experimental investigation on machining of a difficult-to-cut material, AISI D2 steel of hardness 62 HRC with PCBN tools. It was found that the most feasible feeds and speeds fall in the ranges 0.08–0.20 mm/rev and 70–120 m/min, respectively and that most of the tested PCBN tools reached the end of life mainly due to flank wear. The highest acceptable values of tool life...

A non-destructive measuring technique to determine the fiber content in hardened steel fiber reinforced concrete is presented. The technique is based on an accurate open-ended coaxial probe reflectometry method for measuring the effective permittivity of the fiber reinforced concrete and on a mixing rule from the classical homogenization theory for deriving the fiber content from the measured p...

Steel fiber reinforced concrete (SFRC) is used for slabs on grade such as pavements, industrial floors, airport runways, since it exhibits excellent isotropic mechanical properties. When mixing the fibers with the fresh concrete, care is taken to obtain a uniform distribution and a random orientation of the fibers. The strength of this concrete primarily depends on the fiber content, hence it i...

Synopsis: This paper provides the state-of-the-art information on high-calcium, ASTM Class C fly ash use in cement-based construction materials, such as high-performance concrete, ready-mixed concrete, and low-strength flowable concrete. The major topics included are: properties of fly ash, effects of fly ash inclusion on fresh and hardened concrete and controlled low-strength materials (CLSM);...

In this investigation a DoE (Design of Experiments) analysis of distortion for a typical manufacturing process of pre-straightened, cold drawn and induction hardened AISI 1045 cylindrical steel bars was carried out. A careful characterization of the material, including residual stress states and geometrical changes, was done for the different manufacturing steps. In order to identify effects an...

In this paper, the experimental design of using the Taguchi method is employed to optimize the processing parameters in the plasma arc surface hardening process. The processing parameters evaluated are arc current, scanning velocity and carbon content of steel. In addition, other significant effects such as the relation between processing parameters are also investigated. An orthogonal array, s...

INTRODUCTION Hard and temperature resistant materials are used for mold manufacturing of optical glass lenses. These materials are not machinable by ultra precision diamond milling and turning processes. For example hardened steel or tungsten carbide can be ground in optical quality regarding shape but additional polishing is necessary to guarantee the high requirements for optical surface qual...