Summary of basic knowledge of failure analysis and detection of metal materials

Date：2021-09-18 15:30:42Views：1031

The failure form of metal materials is closely related to the failure cause. The failure form is the apparent characteristic of the material failure process, which can be observed in a proper way. The failure reason is the physical and chemical mechanism leading to component failure, which needs to be diagnosed and demonstrated through the investigation and research of failure process and the macro and micro analysis of failed parts. This paper collects and arranges some relevant data of metal material testing, hoping that this paper can be of great reference value to all readers.

Metal materials generally refer to pure metals or alloys in industrial applications, including iron, copper, aluminum, tin, nickel, gold, silver, lead, zinc and so on. The alloy usually refers to two or more metals or materials with metallic properties formed by the combination of metal and non-metal. Metal materials are usually divided into ferrous metals, non-ferrous metals and special metal materials.

Metal material testing field:

Steel materials: structural steel, copper, aluminum, iron, stainless steel, heat-resistant steel, superalloy, precision alloy, chromium, manganese and their alloys;

Steel pipe: carbon pipe, stainless steel pipe, alloy steel pipe, black pipe, galvanized pipe, aluminum plated pipe, chromium plated pipe, aluminized pipe and other alloy coated steel pipe, seamless steel pipe, hot rolled seamless pipe, cold drawn pipe, precision steel pipe, hot expansion pipe, cold spinning pipe, extrusion pipe, straight seam steel pipe, etc.

Alloy products: steel pipe, copper, aluminum, steel plate section steel, welding materials, doors and windows, rolling shutter doors, kitchen supplies, various metal pendant, machine parts, vehicle accessories, etc.

Welding materials: welding rod, flux, welding wire, gas welding powder, solder, etc

Steel wire rope: for elevator, conveyor belt, important use in coal mine, compaction unit, passenger aerial ropeway, export steel wire rope, coarse diameter steel wire rope, etc

Fasteners: bolts, nuts, studs, screws, rivets, washers, retaining rings, welding nails, etc

Metals and their alloys: light metals, heavy metals, precious metals, semi metals, rare metals and rare earth metals;

Special metal materials: functional alloys, metal matrix composites, etc;

Metal material products: pig iron, aluminum pipe, iron plate, iron pipe, ingot, billet, profile, wire rod, metal products, non-ferrous metals and their products, steel, fasteners, cast iron, steel pipe, copper pipe, stainless steel pipe, reinforcement wire rod, welding materials, steel plate section steel, copper aluminum, steel wire rope and various metal pendant and other metal and alloy products.

Metal material test items:

Physical property testing: tensile, bending, yield, fatigue, torsion, stress, stress relaxation, impact, wear, hardness, hydraulic resistance, tensile creep, flaring, flattening, compression, shear strength, magnetic properties, electrical properties, thermodynamic properties, oxidation resistance, density, coefficient of thermal expansion, etc

Chemical properties: atmospheric corrosion, intergranular corrosion, stress corrosion, pitting corrosion, corrosion fatigue, artificial atmosphere corrosion, etc;

Element content analysis: quality (total component analysis), silicon (SI), manganese (MN), phosphorus (P), carbon (c), sulfur (s), nickel (Ni), chromium (CR), copper (Cu), magnesium (mg), calcium (CA), iron (Fe), titanium (TI), zinc (Zn), lead (PB), antimony (sb), cadmium (CD), bismuth (BI), arsenic (as), sodium (NA), potassium (k), aluminum (AL), etc

Process performance test: filament stretching, fracture inspection, repeated bending, bidirectional torsion, hydraulic test, flaring, bending, crimping, flattening, ring expansion, ring stretching, microstructure, etc

Nondestructive testing: X-ray nondestructive testing, electromagnetic ultrasonic testing, ultrasonic testing, eddy current testing, magnetic flux leakage testing, penetrant testing, magnetic particle testing, etc

Metallographic examination: macro metallography, micro metallography (SEM, TEM, EBSD), grain size rating, decarburization layer depth, non-metallic inclusion rating, etc

Environmental reliability: atmospheric corrosion, intergranular corrosion, stress corrosion, pitting corrosion, corrosion fatigue, artificial atmosphere corrosion, salt spray test, etc

Metal brand identification: determine the element content of metal materials and the proportion of each content in the materials through instruments and technical means, so as to confirm the specific brand of materials

Common types of metal material failure:

Failure caused by improper design (unreasonable structural design, insufficient design hardness, improper material selection and unreasonable material state requirements);

Failure caused by material defects (porosity, segregation, subcutaneous bubbles, shrinkage cavities, non-metallic inclusions, white spots, non-metallic inclusions, surface corrosion, etc.);

Failure caused by casting defects (shrinkage cavity and porosity, white mouth and anti white mouth, poor spheroidization of nodular cast iron, slag inclusion, segregation carbide, casting crack, graphite floating, etc.);

Failure caused by forging defects (overheating and overburning, forging cracks, hot embrittlement and copper embrittlement, forging folding, high temperature oxidation, insufficient annealing, forging white spots, forging streamline defects, etc.);

Failure caused by welding defects (welding crack, incomplete penetration and fusion, improper welding preheating, slag inclusion and porosity, intergranular corrosion and stress corrosion);

Failure caused by heat treatment defects (quenching cracks, surface decarburization, carburizing / nitriding defects, tempering cracks, etc.);

Failure caused by cold forming defects (grinding defects, cutting defects, cold heading defects, punching / extrusion / tensile forming defects, etc.).

Inspection standard for metal materials:

GB / T 34558-2017 terminology of metal matrix composites

GB / T 7314-2017 metallic materials room temperature compression test method

GB / T 6398-2017 fatigue test of metallic materials

GB / T 34205-2017 metallic materials hardness test

GB / T 7314-2017e metallic materials room temperature compression test

GB / T 33812-2017 metallic materials fatigue test strain controlled thermomechanical fatigue test

GB / T 246-2017 flattening test of metallic tubes

GB / T 12443-2017 torque controlled fatigue test for metallic materials

GB / T 34477-2017 test for concave resistance of metal materials sheet and strip

GB / T 14265-2017 analysis of hydrogen, oxygen, nitrogen, carbon and sulfur in metallic materials

GB 4806.9-2016 food safety standard metal materials and products for food contact

GB / T 33820-2017 ductility test for metallic materials high speed compression test for porous and honeycomb metals

GB / T 32660.1-2016 metallic materials - Vickers hardness test - Part 1: Test methods

GB / T 4341.2-2016 metallic materials shore hardness test Part 2: verification of hardness tester

The above is the summary of the basic knowledge of metal material failure analysis and detection brought by the core detection. Through this paper, I hope it can be helpful to you. If you like this article, you might as well continue to pay attention to our website, and we will bring more wonderful content later. If you have any needs related to the inspection and testing of electronic products, please call Chuangxin testing, and we will serve you wholeheartedly.