Alloy Steel with H21 High Polishing Mould Steel Plate Metal Sheet Pipe Bar

• Type: Round
• Standard: AISI, ASTM, DIN, JIS, GB, BS
• Composition: Check Detailed Description
• Model NO.: H21
• Technique: Hot Rolled
• Shape: Bar
• Surface Treatment: Black, Machined
• Special Use: High-strength Steel Plate, Wear Resistant Steel, Silicon Steel, Free Cutting Steel, Mold Steel
• Application: Tool Steel Bar
• Transport Package: Nude Packing
• Specification: check detailed description
• Trademark: Ningbo Ningshing
• Origin: China

Product Description

DIN1.2581 Tool Steel | ASTMH21 | JISSKD5 | GB3Cr2W8V

 

Din 1.2581 is a king of hot work tool steel for oil or air solidifying to grow high hot quality, maintenance of hardness, and warmth checking resistance. This is mostly utilized as hot work devices, instruments for manufacture of hollows, screws, rivets, nuts and bolts. Die casting tools, forming dies, die inserts, hot shear blades.

Dimensions
Round: dia.10-700 mm


Specifications
EAF+LF+VD+(ESR), Hot rolled or Forged, Annealed, Black surface or Machined surface, UT SEP1921 Class3 D/d

Equivalence

AISI / SAE	DIN / W.Nr	JIS	GB
H21	1.2581	SKD5	3Cr2W8V

Chemical Composition(%)

Steel Grade	C	Si	Mn	P	S	Cr	V	W
1.2581	0.25-0.35	0.10-0.40	0.15-0.45	≤ 0.030	≤ 0.020	2.50-3.20	0.30-0.50	8.50-9.50
H21	0.30-0.40	0.15-0.30	0.20-0.40	≤ 0.030	≤ 0.030	3.00-3.75	0.30-0.50	8.75-10.00

Applications

1. Highly stressed hot work tools, such as mandrels, dies and containers for metal tube and rod extrusion; hot extrusion tools;
2. Tools for the manufacture of hollows, screws, rivets, nuts and bolts.
3. Die casting tools, forming dies, die inserts, hot shear blades.

Forging Technique

Heat Temperature	Start Forging Temperature	Finish Forging Temperature	Cooling Method
1130-1160 °C	1080-1120 °C	900-850 °C	Slow cooling in furnace or thermoinsulating material

Heat Treatment
Annealing
750 to 800°C (1382 to 1472°F)
Slow controlled cooling in furnace at a rate of 10 to 20°C/hr (50 to 68°F/hr) down to approx. 600°C (1112°F), further cooling in air.
Hardness after annealing: max. 235 HB.

Hardening
1070 to 1150°C (1958 to 2102°F)
Oil, salt bath (500 - 550°C / 932-1022°F), air
Holding time after temperature equalization: 15 to 30 minutes.
Obtainable hardness:
48 - 52 HRC in oil or salt bath,
44 - 48 HRC in air.

Stress relieving
600 to 650°C (1112 to 1202°F)
Slow cooling in furnace; intended to relieve stresses set up by extensive machining, or in complex shapes.
After through heating, hold in neutral atmosphere for 1 - 2 hours.

Tempering
Slow heating to tempering temperature immediately after hardening / time in furnace
1 hour for each 20 mm of work piece thickness, but at least 2 hours / cooling in air.
It is recommended to temper at least twice. A third tempering cycle for the purpose of stress relieving may be advantageous.
1st tempering approx. 30°C (86°F) above maximum secondary hardness.
2nd tempering to desired working hardness.
3rd for stress relieving at a temperature 30 - 50°C (86 to 122°F) be low highest tempering temperature.

Q1: What is Ningbo Ningshing Precision Machinery Group Co., Ltd ?
A1: Ningbo Ningshing Precision Machinery Group Co., Ltd., formerly known as Ningbo Ningshing Special-Steel Group Co., Ltd., is the leading distributor of Special Steel, and also a professional mold base maker in China. Our business involves special steel trading, machining processing, mold base making, heat treatment, CNC machines manufacturing.


Q2: Are you a manufacturer or a trader? 
A2: For Special Steel, we are the one of the leading distributors and service center in China. 9 warehouses with over 50,000 tons of regular stock. Our workshop has various kinds of equipments for sawing, milling, grinding, drilling etc.
For mold base, we are a professional manufacturer, with 24 sets of CNC machines, 3 axis and 5 axis, CMM for inspection. We produce medium-large sized mold base for plastic injection mold and die casting die.


Q3: How do you control the quality of steels?
A3: Firstly, we have very close and deep relationship with Chinese Prime Mills, choose supplier carefully, and regard them as the long term business partner. Based on the long term cooperation, we concentrate on special steel business and expand the market step by step. Secondly, we have own technical center which is formed by the experienced engineers and technicians whom ever worked for prime mills. We control the quality in production process, in-out warehouse.


Q4:: Which kind of processing can you do?
A4: We do machining processing like cutting, milling, grinding, turning, peeling, drilling, CNC machining. Meanwhile, we do vacuum heat treatment for die and mold.