6. AISI S7 Tool Steel Heat Treatment

Annealing

    Anneal in a protective atmosphere. Heat rapidly to 1500 to 1550°F and hold at that temperature for one and one-half hours for each inch of greatest thickness. To obtain best machining properties, cool slowly to 1000°F, and then air-cool. This annealing procedure should produce a hardness of Brinell 197 max.
Stress Relief S7 steel Material: When desirable to relieve the strains of machining, heat slowly to 1050°-1250°F, allow to equalize, then cool in air.

Hardening

    Preheat: Warm steel S7 slightly before charging into the preheat furnace 1200°-1300°F, prior to hardening.

Harden: 1750°F. Quench S7 tool steel in air if cross section is 2-1/2″ or smaller; sections 2-1/2″ to 6″ should be oil quenched to black (1000°F) followed by air cooling to 150°F. Larger cross sections of S7 steel should be oil quenched to 150°F.

    Quench: Quench in still air or dry air blast.

    Temper: Tool steel S7 is normally tempered one hour per inch of section thickness to desired heating rate of 2 hours per inch. Cool in air to room temperature between the two tempers. The tempering temperature varies according to the intended use. Suggested: For cold-working and similar applications, the recommend400°-500°F. Hot working applications: apply a tempering temperature of 900°-1000°F. Never temper at less than 400°F.

    For hot rolled plate, usually the delivery condition is hot rolled, annealed, black surface.

Hunan Qilu Industrial Co., Ltd has the capacity to forge round steel, steel flat, square steel, module, shaft and roller, etc. The main specifications of the products include Φ80-1000mm forging materials and 80-1200mm square billets and which the maximum piece weight can reach 50T.







Hunan Qilu Industrial Co., Ltd were already engaged in exporting steel for 11 years, could supply a great variety of hot forged, hot rolled and cold drawn Steels,  including engineering steel, cold work tool steel, hot work tool steel, plastic mold steel, spring steel, high speed steel, stainless steel etc., besides Qilu Industrial also has their own heating treatment shop and machining shop to provide heating and cutting service.

Since 2008 year, Hunan Qilu Industrial has the right to export all FORGED STEEL behalf of Qilu Speical Steel Co.,ltd which is specialized in smelting and forging of special steel since 1965 year, now Qilu special steel is one of the biggest manufacturer of forged product in China.The forged products are used in Automotive, Aerospace, Power Generation, Oil & Gas, Transportation and Industrial. We already set up the warehouse in Wuxi and Dongguan city, more than 20000 tons ex-stock could be supplied with kinds of size.

Qilu Industrial is the professional one-stop steel manufacturer, stockist and exporter in China, our customers spread all over the world, include West Europe, North America, South America, Asia, Middle Asia, Africa, Australia, etc.







The company owns advanced special steel smelting facilities and forging processing equipments, the main steel-making equipment include 2 sets of 50t ultra-high power electric arc furnaces,2 sets of 60t LF refining furnaces,1 set of 60t vacuum degassing refining furnace and 4 sets of 1-20t electroslag re-melting furnaces.
The main forging equipments mainly include:3 sets of 5t electro-hydraulic hammers, 1 set of high-speed forging units of 800t,1600t,2000t and 4500t respectively.













Hunan Qilu Industrial CO., LTD
Web: qilusteel.en.made-in-china.com