Search Results for rebound methods

This article describes a method for determining the dynamic indentation response of metals and ceramics. This method, based on split Hopkinson pressure bar testing, can determine rate-dependent characteristics of metals and ceramics at moderate strain rates. For example, dynamic indentation testing reveals a significant effect of loading rates on the hardness and the induced plastic zone size in metals and on the hardness and induced crack sizes of brittle materials. The article also explains the rebound and pendulum methods for dynamic hardness testing.

Miscellaneous hardness tests encompass a number of test methods that have been developed for specific applications. These include dynamic, or "rebound," hardness tests using a Leeb tester or a Scleroscope; static indentation tests on rubber or plastic products using the durometer or IRHD testers; scratch hardness tests; and ultrasonic microindentation testing. This article reviews the procedures, equipment, and applications associated with these alternate hardness test methods.

Mechanical testing is an evaluative tool used by the failure analyst to collect data regarding the macro- and micromechanical properties of the materials being examined. This article provides information on a few important considerations regarding mechanical testing that the failure analyst must keep in mind. These considerations include the test location and orientation, the use of raw material certifications, the certifications potentially not representing the hardware, and the determination of valid test results. The article introduces the concepts of various mechanical testing techniques and discusses the advantages and limitations of each technique when used in failure analysis. The focus is on various types of static load testing, hardness testing, and impact testing. The testing types covered include uniaxial tension testing, uniaxial compression testing, bend testing, hardness testing, macroindentation hardness, microindentation hardness, and the impact toughness test.

This article discusses the tests designed specifically to evaluate the adhesion, friction, and wear behavior of various material systems. It tabulates the characteristics of common types of wear and mechanical surface damage. The article also considers the displaying and analyzing of adhesion, friction, and wear test data. It concludes with a description of devices used for testing adhesion, friction, and wear.

This article reviews the various types of mechanical testing methods, including hardness testing; tension testing; compression testing; dynamic fracture testing; fracture toughness testing; fatigue life testing; fatigue crack growth testing; and creep, stress-rupture, and stress-relaxation testing. Shear testing, torsion testing, and formability testing are also discussed. The discussion of tension testing includes information about stress-strain curves and the properties described by them.

This article emphasizes the traits that are common to high-velocity forming operations. It describes general principles on how metal forming is accomplished and analyzed when inertial forces are large. The article discusses the principal methods of high-velocity forming, such as explosive forming, electrohydraulic forming, and electromagnetic forming. It provides examples that illustrate how these methods can be practically applied. The article concludes with information on the status and development potential for the technology.

This article introduces the general principles and applications of heat treatment to iron castings. It provides a detailed discussion on the heat treatment processes, namely, stress relieving, annealing, normalizing, throughhardening, and surface hardening for various types of cast irons. These include gray iron, ductile iron, compacted graphite iron, white iron, malleable iron, and high-alloy iron. The article describes how to control temperature and atmosphere during the heat treatment of the iron castings.

Materials resulting from thermal spray processes are often different from their wrought, forged, and cast counterparts. Assessing the usefulness of thermal spray coatings requires understanding, developing, and using appropriate testing and characterization methods that are generally borrowed from other materials science disciplines. This article focuses on commonly used testing and characterization methods: metallography, image analysis, hardness, tensile adhesion testing, corrosion testing, x-ray diffraction, non-destructive testing, and powder characterization. It provides information on how the materials themselves respond to the various test methods. The article focuses on the test methods themselves, including those test parameters that can be varied and the influence of each on the results obtained.

This article is a compilation of terms related to mechanical testing and evaluation of metals, plastics, ceramics, and composites.

This article provides information on the factors influencing the selection of the proper corrosion-resistant coating system. It focuses on the proper execution of surface preparation and the available surface preparation methods. The preparation process includes the removal of visible contaminants, removal of invisible contaminants, and roughening of the surface. Solvent or chemical washing, steam cleaning, hand tool cleaning, power tool cleaning, water blasting, and abrasive blast cleaning, are some preparation methods discussed. The article describes the most common application techniques of coating as well as the equipment used. An overview of some of the most common coating inspection points and inspection equipment is also provided.

A wide range of flow-formed open- and close-ended shapes are currently available in a variety of difficult-to-form materials, including titanium alloys and nickel-base super alloys. This article describes the two basic methods of flow forming that are characterized by the position of the rolls during the forming process. The flow forming methods include staggered-roll flow forming process and in-line flow-forming process. Typical mechanical properties of flow-formed materials in various conditions are summarized in a table. Proper process controls and subsequent product qualification tests are critical to assure optimal performance of the flow-formed tubular component. The article discusses the most commonly required process control parameters and the effects of forming speed and temperature in the flow forming process.

This article addresses the important variables in erosion, such as particle impact velocity; particle impact angle; particle size, shape, and material; and ambient temperature. It describes four erosion test methods: the gas-blast method, a method using a centrifugal accelerator test rig, the wind-tunnel test, and the whirling arm test. The article also details the various test methods used to measure impact velocity of particle and data analysis and interpretation of these four methods.

Rehabilitation is the process of repairing or modifying reinforced concrete structures to a desired useful condition. This article describes the operational steps for the structural assessment of reinforced concrete structures. It discusses the classification of composite materials reinforcing systems for strengthening reinforced concrete structures, such as shop-manufactured and field-manufactured structures. The article reviews the materials property requirements for designing reinforcing systems to strengthen the reinforced concrete structures. It discusses the fiber-reinforced polymer (FRP)-reinforced concrete behavior that depends on flexural, shear, or axial failures. Surface preparation procedures for rehabilitation techniques of reinforced concrete structures using bonded FRP materials are also discussed. The article provides information on the applications of rehabilitation of concrete structures. It explains data recording and acceptance criteria for rehabilitation of concrete structures with composite materials.

This article provides an overview of cavitation erosion with a specific focus on the estimation of mass loss. It describes the mechanisms of cavitation erosion and the types of laboratory devices to evaluate the resistance to cavitation erosion of materials. The laboratory devices include rotating disks, vibratory devices, cavitating liquid jets, and high-speed cavitation tunnels. The article discusses materials selection and surface protection to prevent cavitation erosion. It reviews the fluid-structure interaction that plays a role in cavitation erosion particularly for compliant materials. The article provides information on the numerical prediction of cavitation erosion damage by the finite element method (FEM).

Hardness testing is perhaps the simplest and the least expensive method of mechanically characterizing a material. This article provides an overview of the principles of hardness testing. It compares Brinell with Meyer hardness testing and hardness testing of fully cold worked metals with fully annealed metals. The article discusses the plastic deformation of ideal plastic metals under an indenter, by a flat punch, and by spherical indenters. The classification of the hardness tests using various criteria, including type of measurement, magnitude of indentation load, and nature of the test, is also provided.

Solid particle erosion (SPE) is the loss of material that results from repeated impact of solid particles energized in a carrier fluid. This article reviews important SPE variables, their effects for different classes of materials, composites and coatings, and the mechanisms and theories proposed to explain SPE. It discusses the SPE of metals, steels, and ceramics, as well as erosion of alloys with coarse, nominally two-phase microstructures in which the second-phase particles (SPPs) are typically large compared with the dimensions of the damage zone created by the impact of one particle. The article summarizes the erosion characteristics of polymer matrix composites (PMCs), metal matrix composites (MMCs), ceramic matrix composites (CMCs), and erosion-resistant coatings. The combination of parameters included in most erosion models is also summarized.

The purpose of continuous casting is to bypass conventional ingot casting and to cast to a form that is directly rollable on finishing mills. The use of this process has resulted in improvement in yield, surface condition, and internal quality of product when compared to the ingot-made material. This article outlines the advantages of steel continuous casting, along with its developments and challenges for improvement. It provides a general description of the continuous casting process and the design and layout of a continuous casting steelmaking facility. It reviews process enhancements such as near-net shape casting, tundish metallurgy, and pouring stream protection. The article discusses the use and capabilities of different molds for steel continuous casting, including thin-wall tube-type molds, solid molds, and plate molds. The article explains the methods for enhancing productivity and improving quality in steel continuous casting. It evaluates the applications of horizontal continuous casting in casting steel. The article concludes by outlining priorities for future development such as enhanced control systems and automation.

Maintenance coating is an important part of any meaningful asset-preservation strategy in facilities producing pulp and paper and other chemicals. This article discusses maintenance coating for carbon steel structures and process equipment exposed to normal external pulp and paper mill atmospheric conditions. The important requirements and standards for surface preparation are emphasized and common issues encountered in maintenance coating projects are described.