HEAT TREATMENTS ON NICKEL AND ALLOYS
The alloys with high percentage of nickel are used for the exposure to high temperature or highly corrosive agents, or in presence of both conditions.
Nickel alloys are divided in function of the main element and of the secondary ones:
Nickel - Carbon: Nickel 200 - Nickel 201
Nickel - Copper: Monel 400
Nickel - Chromium: Nimonic 80A, Nimonic 90
Nickel - Chromium - Iron: Inconel 600
Nickel - Chromium - Iron - Molybdenum - Copper: Hastelloy G
Nickel - Chromium - Iron - Molybdenum - Cobalt: Hastelloy X
Nickel - Chromium – Molybdenum - Niobium: Inconel 625
Nickel - Molybdenum: Hastelloy B
Nickel - Molybdenum - Chromium: Hastelloy C276
Nickel - Iron: Invar
Nickel - Iron - Chromium: Incoloy 800, Incoloy 825
The heat treatments that are generally executed in the metallurgy of Nickel are "annealing", "solution annealing and aging" and "stress-relieving".
The annealing heat treatment generates particularly soft final structure, ideal (PERFECT) for the execution of mechanical work machining, forming or welding. Many alloys for the contstruction are bought in this state at the beginning.
Solution annealing consists in heating an alloy at an adequate temperature, maintaining that temperature for a sufficient period of time to cause the transformation of one or more constituents into a solid solution and, therefore (AFTER THAT) cooling it in a sufficiently rapid way in order to maintain those components in the solution.
The annealing is generally performed at temperatures between 1800 and 2450°F, followed by a rapid cooling at ambient temperature. Many materials have specific cooling speeds that must be reached in order to obtain the correct metallurgical microstructure in the final product.
Aging heat treatments
Aging is generally performed at temperature between 1000 and 2080°F in inert atmosphere or air, for soaking times that span from (MANCA FORSE QUALCHE DATO?) according to the exact material and the specified metallurgical microstructure. To obtain the desired final results, various stages could be necessary (with reduction of temperature in each phase).
Executed at a lower temperature than annealing or solution annealing, stress relieving reduces the residual stresses caused by welding and mechanical working processes, reducing (LOWERING?) the stress-corrosion cracking phenomenon.
On the components with the highest value, which undergo strict testings and with treatments monitored by third institutions, it is important that our customers can count on a structured and reliable supplier as TRATER, which is provided with personnel and means to execute the thermal cycles at best and deliver items always correctly treated (vedi precedenti).
TRATER counts more than 45 employees. The core of the company is the technical office with 12 specialists, engineers and quality personnel. A department of 9 persons, divided into three shifts, operating 24 hours a day, handles exclusively with the monitoring of thermal cycles. They have been trained through specific metallurgical courses, welding technologies, modeling of thermal systems, combustion systems, electro-technics and measurements; they attend a training and continuous updating program. The heat-treatment personnel constantly controls, interacting with the automatic systems of the ovens, that the items under treatment reach the soaking temperature and remain in it for the prescribed time, in all of their parts.