What is Impact toughness?
What is impact toughness?
Impact toughness is the ability to reflect the metal to the external impact load resistance, generally by the impact toughness (ak) and impact (Ak) said, the unit were J / cm2 and J (Joule). Impact toughness or impact test (referred to as "impact test"), due to the test temperature is divided into normal temperature, low temperature and high temperature impact test three; according to the specimen gap shape can be divided into "V" Shape notch impact test two.
Impact test: with a certain size and shape (10 & # 55; 55 mm) of the sample (the length of the middle of the "U" or "V" type gap, notch depth of 2mm) in the specified test machine by the impact The experiment of breaking the gap from the gap.
A, the impact of absorbing power Akv (u) - has a certain size and shape of the metal pattern, under the impact of the impact of the load absorbed by the work. The unit is Joule (J) or Kgf. M.
B, impact toughness value akv (u) - shock absorption power divided by the bottom of the specimen at the bottom of the cross-sectional area of the business. The unit is Joule / cm 2 (J / cm2) or kgg. M / cm 2 (Kgf. M / cm2).
The formula is: where: Akv (u) - the energy absorbed by the specimen breaking, Kgf. M (J); S - the bottom cross section of the specimen notch, cm2. Temperature test temperature of 20 ℃ 50C; low temperature impact test temperature range of <15 ~ -1920C; high temperature impact test temperature range of 35 ~ 10000C. The cooling medium used in the low-temperature impact test is generally non-toxic, safe, non-corrosive to metals and liquids or gases that are not solidified at the test temperature. Such as anhydrous ethanol (alcohol), solid carbon dioxide (dry ice) or liquid nitrogen atomization gas (liquid nitrogen) and so on.