Starting back about 150 years ago Swiss watchmakers gave birth to cryogenics. They would bury their watch parts in the snow for a winter because they noticed that it would make them more durable and therefore keep better time. After that it was the tool and die makers of the 1930’s that noticed that freezing tool steel would help it hold an edge better than tool steel that hadn’t been frozen. By the 1940’s it was commonplace to see shop yards with castings sitting out over the season so that the hot and cold weather would stress relieve it. From this came the term “seasoned” and this is a practice and term used today. NASA started cryogenics as a science. In the mid 1960’s NASA scientists noted that many of the materials used in spacecraft were some how improved once they were subjected to the hot and cold of space. They started to study why and helped to start this emerging field. NASA still uses cryogenics and is further studying its effects on all types of materials. By the 1970’s word got out that cryogenics was the wave of the future, but no one knew what they were doing. So they would throw parts into liquid nitrogen and cause thermal shock. From that people were then turned off and it is a stigma that still exists with a few people. By the mid 1980’s more knowledge on how to properly treat parts started to surface. Company’s started to offer this to the public and studiesf followed on its effects and what it could do.