Metallographic analysis

Background introduction

Under the optical microscope, the study of the law of metal material structure is called "metallography". Metallographic analysis is an indispensable and important means for testing material structure and ensuring product quality. With the development of science and technology, especially optical technology, the use performance of optical microscope is gradually expanding, such as dark field, polarized light, phase contrast, differential interference, infrared light and ultraviolet light, which improve the definition and resolution of metallographic structure.

Analysis items and standards

Test materials test items test standards

Iron and steel materials: conventional analysis, decarburization layer, inclusions, grain size (including general steel and stainless steel), hardness gradient, macro sample, welding structure (including heat affected zone, weld, base metal)

GB/T 6462-2005，GB/T 13299-1991，JB/T 7710-2007，JB/T 7713-2007，GB/T 13320-2007，GB/T 11354-2005，JB/T 9211-1999，JB/T 6141.2-1992，JB/T 6141.3-1992，QC/T 29018-2005 QC/T 262-2005，GB/T 1299-2000，JB/T 1255-2001，GB/T 7216-1987，GB/T 9441-1988，JB/T 9204-1999，GB/T 14979-1994，GB/T 9450-2005，ISO 2639:2002(E)，GB/T 9451-2005，I SO 4970:1979(E)，GB/T 224-1987，ISO 3887:2003(E)，GB/T 5617-2005，ISO 3754:1976(E)，GB/T 10561-2005，GB/T 4335-1984，

ASTM E45-2005e2，DIN 50602-1985，YS/T 347-2004，

GB/T 3246.1-2000，GB/T 9441-1988，GB/T 7216-87

GB/T 6394-2002，ASTM E112-1996(2004)e2

Microstructure and grain size of copper and copper alloy (QJ 2337-1992, YS / T 347-2004)

Aluminum and aluminum alloy casting aluminum alloy metallographic casting aluminum silicon alloy modification JB / T 7946.1-1999

Cast aluminum alloy metallographic cast aluminum silicon alloy overburning JB / T 7946.2-1999

Casting aluminum alloy metallographic casting aluminum alloy pinhole JB / T 7946.3-1999

Casting aluminum alloy metallographic casting aluminum copper alloy grain size JB / T 7946.4-1999

Test method for microstructure of wrought aluminium and aluminium alloy products GB / T 3246.1-2000

Test flow

For metallographic analysis, first of all, the samples should be prepared according to various inspection standards and regulations. If the samples are not prepared properly, there may be false images, so the wrong conclusions can be drawn. Therefore, the preparation of metallographic samples is very important. Generally, the preparation steps of metallographic samples are: sampling, inlay, marking, grinding, polishing and etching. But not every metallographic sample must go through the above steps. If the shape and size of the selected sample are suitable for gripping and grinding, it is unnecessary to inlay. If non-metallic inclusions in metallic materials or graphite in cast iron are examined, etching is not necessary. In a word, the sample preparation procedure should be determined according to the inspection purpose.

Test equipment

The metal laboratory is equipped with a complete set of metallographic sample making equipment produced by Buehler in the United States and a positive metallographic microscope produced by Zeiss in Germany, which can realize professional metallographic analysis from ferrous metals to non-ferrous metals.