20Cr2Ni4A/30NC14

1. 牌号 Grade20Cr2Ni4/30NC14

GB	DIN	W-Nr.	AISI	JIS	BS	EN
20Cr2Ni4					30NC14

2. 执行标准 Standard GB/T3077-2015
3. 尺寸、外形、允许偏差 Size , shape ,tolerance

状态 condition	公差 tolerance
磨皮 grinding surface	-0/+5mm
车削 machined surface	-0/+3mm
自由长度 free length	4-6m
定尺长度 fixed length	-0/+50mm
超长 over long	7-23m
弯曲度 straightness	≦3mm/m, 总弯曲度total straightness length ≦ total length总长度0.5%
不圆度 ovality	不大于公称直径公差的0.7倍 Not greater than 0.7 times the nominal diameter tolerance
锻材生产直径范围forged bar dia range	140-600mm

4. 冶炼方法 smelting process

电弧炉+炉外精炼+真空脱气冶炼，下注钢锭，电渣重熔需在合同中注明 EAF+LF+VD bottom pour ingot, ESR need indicate in contract

5. 交货状态 delivery condition

退火磨氧化皮、车光、正火、调质，交货状态需合同注明 annealed grinding surface. If need machining, normalizing or Q&T need
indicate in contract

6. 化学成份 chemical composition

牌号grade	C	Si	Mn	P≦	S≦	Cr	Ni	Mo	V
20Cr2Ni4	0.17/0.23	0.17/0.37	0.30/0.60	0.025	0.025	1.25/1.65	3.25/3.65

其他元素检测需要合同注明 other elements test result need indicate in contract.

7. 力学性能,交货硬度 mechanical property,hardness

推荐的热处理制度Recommended heat treatment regime					力学性能mechanical property					退火或回火交货硬度annealed or tempered HBW
淬火quenching			回火tempering		抗拉强度 tensile MPa	屈服强度yield MPa	伸长率 elongation A%	收缩率shrinkage Z%	冲击功impact J
加热温度℃ heating		冷却剂coolant	加热温度℃ heating	冷却剂coolant
第1次淬火first time quenching	第2次淬火 2rd quenching				不小于 ≧					不大于 ≦
880	780	油oil	200	水、空气	1180	1080	10	45	63	269

8. 低倍组织 酸浸低倍试片上不得有目视可见的缩孔、夹杂、分层、裂纹、气泡和白点。Macrostructure No visible shrinkage,
8. inclusion, delamination, cracks, bubbles or white spots should be observed on the acid – soaked sample piece 

钢材直径diameter mm	1组 group		2组 group
	中心疏松 center porosity	锭型偏析segregation	中心疏松center porosity	锭型偏析segregation
	级，不大于 class ≦
≦80	2.0	2.0	3.0	3.0
>80-150	2.5	3.0	3.5	3.0
>150-250	3.0	3.0	4.0	4.0
>250-400	3.5	3.0	4.5	4.0
>400	协商 Negotiate

电渣钢合格级别供需双方协议 ESR steel qualified level need negotiate.

9. 显微组织 microstructure

1. 珠光体组织 合格级别1-5级，热压力加工用钢不检测 pearlite 1-5 class
2. 网状碳化物 直径不大于60MM合格级别不大于3级 carbide network ≦ 3 class
3. 共晶碳化物不均匀度（冷作模具钢检测）Eutectic carbide inhomogeneity

钢材直径diameter MM	共晶碳化物不均匀度合格级别Eutectic carbide inhomogeneity qualified level
	1组group	2组 group
	级，不大于 class ≦
>120-400	6	协议Negotiate
>400	协议Negotiate	协议Negotiate

10. 非金属夹杂物 nonmetallic inclusion

电渣钢结果符合1组，真空脱气钢符合2组 ESR steel conform to 1 group , VD steel conform to 2 group

非金属夹杂物类别nonmetallic inclusion type	1组 group		2组 group		DS
	细系thin series	粗系heavy series	细系thin series	粗系heavy series
	级，不大于 class ≦				≦
A	3.0	2.5	2.5	2.0	2
B	3.0	2.0	2.5	1.5
C	2.0	1.5	1.5	1.0
D	2.0	1.5	1.5	1.0

11. 脱碳层 decarburized layer

脱碳层深度不大于0.25+1%D,直径大于150mm双方协议 decarburized layer depth not greater than 0.25+1%D, diameter over 150mm
negotiate.

12. 超声检测 UT test

执行标准GB/T6402-2008,常规规格执行D/d级，直径400以上双方协议，钢材内部不允许有白点、夹渣、分层、内裂、缩孔等冶金缺陷
standard as per GB/T6402-2008 /SEP1921 C/c or D/d class. No white spot, slag inclusion, delamination, cracking, shrinkage
and other metallurgical defects are allowed inside the steel

缺陷尺寸级别 defect size level	单个缺陷平底孔直径single FBH mm	连续缺陷平底孔直径continuous FBH mm	连续缺陷最大长度continuous FBH length mm
C	7	5	40
D	5	3	30
E	3	2	30

 

缺陷数量级别defect qty level	单个缺陷数量single FBH QTY	连续缺陷数量continuous FBH QTY
	个数，不大于 number ≯
c	8	4
d	4	2
e	2	1

13. 表面质量 surface quality

锻材表面没有目视可见的裂纹、折叠、结疤和夹杂，如有上述缺陷就清除，深度不大于截面尺寸4%，清除宽度不小于深度的5倍，
There are no visible cracks, folds, scars or inclusions on the surface. If there are any of the above defects, they should be
removed with a depth not greater than 4% of the section size and a width not less than 5 times of the depth.

14. 特殊要求 special requirements

超出标准约定范围的供需双方协议 The buyer and the seller negotiate beyond the agreed scope of the standard

15. 起订量30吨以上，交货期30天 MOQ 20-35 tons, 30 days delivery time.
16. 特点及用途  features and applications: 用作强度要求较高的渗碳及调质结构件 Used for carburizing and quenching structures
16. with high strength requirements

 
优势 advantage
工艺成熟，炼钢采用气体保户浇注，快锻机开坯，径锻机成材，锻造频率高恒温锻造有利于得到较好钢材内部组织。
The process is mature, pouring by gas protected, blooming by fast forging machine, forming by radial forging machine, forging with high
frequency and constant temperature is beneficial to get better steel internal organization.