Changes
/* groupe 1.72xx, Cr-Mo(-B) avec Mo < 0,35% */
exemples de tubes carrés et rectangulaires vendus en Amérique: [http://www.aircraftspruce.com/catalog/mepages/4130square.php Aircraft Spruce], [http://aircraftproducts.wicksaircraft.com/viewitems/aircraft-metal-tubes-channels-angles/4130-rectangular-steel-tubing Wicks Aircraft], [http://www.stockcarsteel.com/4130-chrome-moly/4130-chrome-moly-square-tube Stockcar Steel], [http://www.factorysteel.com/aircraft-tubing.htm#Tubing Factory Steel]
[https://www.grantadesign.com/userarea/Mil/mil5_mainpdf2_3.htm infos MIL-HDBK-5-H (§2.3)], [http://everyspec.com/MIL-HDBK/MIL-HDBK-0001-0099/MIL_HDBK_5J_139/ download MIL-HDBK-5-J (complet, aller au §2.3)]
| 10083 (aciers trempables),
