Showing posts with label Heat Treat Furnace. Show all posts
Showing posts with label Heat Treat Furnace. Show all posts

Industrial Heat Treatment Furnaces, Big and Small

Here at Hotfoil-EHS, we are capable of building furnaces of many sizes, big and small. From small, low-throughput furnaces, to much larger high yield furnaces, to rail-driven furnaces designed to move back and forth over the materials being heated, Hotfoil-EHS Design Engineers and Fabrication Shop has done it all. Gas or electric, Hotfoil-EHS has the experience to build a custom furnace to your exact specification.  If you can think it, we can build it!

Hotfoil-EHS
https://hotfoilehs.com
609-588-0900

Hotfoil-EHS Manufacturing and Distribution Facilities

Hotfoil-EHS, Inc. is an organization with over 70 employees and an impressive engineering capability. Through continued re-investment of profits, Hotfoil-EHS acquired additional large fabrication facilities and today is a full-service engineering, design, and manufacturing company of industrial heating equipment. Their Hamilton, NJ headquarters provides 68,000-square-feet of manufacturing space, with other manufacturing and distribution facilities located in Chattanooga, TN, LaPorte, TX, and Birmingham, England.

609-588-0900

The Importance of Post-weld Heat Treatment for Welding Repairs

welding
Welding is the process of melting two metals together. During the welding process, the metal is exposed to very high temperatures and undergoes a phase change, first from solid to liquid, then back to solid as it cools.

During welding, residual stresses are formed in an area referred to as "the heat affected zone" or HAZ. In the HAZ, differential contractions occur as the metal heats, liquifies and then cools to ambient.

Residual stresses have a significant impact on the performance of a weld and their reduction is highly desirable. The undesirable impact of residual stresses in welded metal structures involve fatigue performance and corrosion resistance.

heat treating furnace
Heat treatment furnace.
pwht with resistance heaters
PWHT with resistance heaters
Welding repairs are increasingly a structural integrity concern for aging  equipment such as pressure vessels, piping systems and other large steel systems. The make up of residual stresses near repair welds can be drastically different from those residual stresses of the original weld.  Post-weld heat treatment (PWHT) is used to reduce residual stress in steel and and should be used for welding repairs ( as well as on new welds).

PWHT is proven very effective in reduction of high residual stress around the weld repair. Conventional PWHT can be done by combustion furnace, induction heaters or electric resistance heaters (ceramic pad heaters). Accurate ramp and soak times, as well as data recording can be done with modern power console systems. It is strongly recommended to apply PWHT for all original and repair welds.

Basics of Heat Treating

Heat treating furnace
Interior view of heat treating furnace.
Heat treating refers to the heating and cooling operations performed on metal work-pieces to change their mechanical properties, their metallurgical structure, or their residual stress state.

Heat treating includes stress-relief treating, normalizing, annealing, austenitizing, hardening, quenching, tempering, martempering, austempering, and cold treating. Annealing, as an example, involves heating a metallic material to, and holding it at, a suitable temperature, followed by furnace cooling at an appropriate rate. Steel castings may be annealed to facilitate cold working or machining, to improve mechanical or electrical properties, or to promote dimensional stability.  Steel vessels, girders, pipes, and structures are heat treated prior to, and after welding to improve weld quality and strength.

Gas fired furnace used for heat treating.
Gas fired furnace used for heat treating.
Heat treating is performed in conventional furnaces, salt baths, or fluidized-bed furnaces. The basic conventional furnace consists of an insulated chamber with an external reinforced steel shell, a heating system for the chamber, and one or more access doors to the heated chamber.

Heating systems are direct fired or indirect heated. With direct-fired furnace equipment, work being processed is directly exposed to the products of combustion, generally referred to as flue products. Gas- and oil-fired furnaces are the most common types of heat treating equipment. Indirect heating is performed in electrically heated furnaces and radiant-tube-heated furnaces with gas-fired tubes, oil-fired tubes, or electrically heated tubes.

Custom Built Heat Treat Furnaces

Custom Built Heat Treat Furnaces
 15'x15'x60' Custom Furnaces
Hotfoil-EHS has extensive heat treating furnace design and fabrication experience. From small, low-throughput furnaces, to much larger high yield furnaces, to rail-driven furnaces, Hotfoil-EHS Design Engineers and Fabrication Shop have done it all.


 Heat Treat Furnace
Capable of handling 45,000 lbs.
Recently Hotfoil-EHS provided a customer with a heat treat furnace that is 15'x15'x60' that accommodates up to 45,000 pounds of material. Two, 5 million BTU burners heat the furnace to 1650 deg. F. The furnace travels on a track, back and forth, to accommodate two beds for greater production.

 Heat Treat Furnace
Rail system with (2) beds


For more information, visit http://www.hotfoilehs.com or call 609.588.0900.