Steel file is a kind of hand tool widely used in various
industries, and is made of carbon tool steel for a long
time. This seriously affects the possibility of file
manufacturing industry to adopt a variety of forming
processing methods. From the actual use of the file, the
file is a kind of hand tool without re-grinding, it
requires good cutting performance, chip removal
performance, and higher service life. For this reason,
the tooth peak of the file should have enough hardness,
strength, fatigue resistance, as well as high wear
resistance and corrosion resistance, and for its center,
it requires better toughness and impact resistance.
However, the carbon tool steels used nowadays do not have
such characteristics as external strength and internal
toughness.

所以，长期以来，国内外钢锉业界的广大工程技术人员不断探寻
新材料、新技术、新工艺。早在1972年罗马尼亚曾研制出用低碳
钢进行表面液体碳氮共渗的方法来制造锉刀。我国也曾在20世纪
60年代至80年代进行过用低碳钢制作锉刀的试验。这些方法或者
是因为有严重公害，或者是因为效益欠佳、性能不高，都没有得
到广泛应用，以致至今国内外广大锉刀业仍首选采用T12或T13制
造。而北京某厂研制出的低碳钢钢锉碳氮共渗新工艺，值得借
鉴。

Therefore, for a long time, the vast number of engineers
and technicians in the steel filing industry at home and
abroad have been exploring new materials, new technology
and new technology. As early as 1972, Romania developed a
low carbon steel surface liquid carbonitriding method to
manufacture files. China also conducted tests on making
carbon files from low carbon steel between 1960s and 80s.
These methods have not been widely used either because of
serious pollution, or because of poor efficiency and low
performance. So far, the filing industry at home and
abroad still preferred to use T12 or T13. A new process
for carbonitriding of low carbon steel files made by a
factory in Beijing is worth learning from.

1)盐浴碳氮共渗配方及热处理工艺。中温、高效、无毒的碳氮共
渗剂配方（质量分数）为：

1) salt bath carbonitriding formula and heat treatment
process. Medium temperature, high efficiency, non-toxic
carbonitriding agent formulation (mass fraction) is:

75%BaCl2+20% NaCl+3.5% Na2CO3+1.5% NaCNO（氰酸钠）

75%BaCl2+20% NaCl+3.5% Na2CO3+1.5% NaCNO (sodium cyanate)

在工作状态盐浴进行的主要化学反应为

The main chemical reactions in the salt bath are in the
working state.

2NaCNO+O2→Na2CO3 +2[N] +CO

2NaCNO+O2 to Na2CO3 +2[N] +CO

4NaCNO→2NaCN+Na2CO3 +CO+2[N]

4NaCNO to 2NaCN+Na2CO3 +CO+2[N]

2NaCN+Na2CO3→2Na2O+2[N]+2[C]+CO

2NaCN+Na2CO3 to 2Na2O+2[N]+2[C]+CO

2NaCN+3Na2CO3→4Na2O+2[N]+5CO

2NaCN+3Na2CO3 to 4Na2O+2[N]+5CO

2CO→CO2+[C]

2CO to CO2+[C]

盐浴中的BaCl2能促进渗碳并抑制产生NaCN：

BaCl2 in salt bath can promote carburization and inhibit
the production of NaCN:

2NaCN+BaCl2→2NaCl+Ba(CN)2

2NaCN+BaCl2 to 2NaCl+Ba (CN) 2

Ba(CN)→BaCN2（氰胺基化钡）+[C]

Ba (CN) to BaCN2 (cyanamide barium) +[C]

盐浴中的BaCl2还能与盐浴中存在的Na2CO3直接作用，生成稳定的
BaCO3与BaO，以及一部分NaCNO：

BaCl2 in salt bath can also react directly with Na2CO3 in
salt bath to form stable BaCO3 and BaO, and some NaCNO:

BaCl2+Na2CO3→BaCO3 +2NaCl

BaCl2+Na2CO3 to BaCO3 +2NaCl

BaCN2+Na2CO3→BaO+2NaCNO

BaCN2+Na2CO3 to BaO+2NaCNO

生成的BaCO3与BaO可通过捞渣去除。成分中NaCl的存在，主要是
为了调节盐浴的熔点，增加盐浴的流动性，从而加强传热过程。

The generated BaCO3 and BaO can be removed by slag
removal. The presence of NaCl in the composition is
mainly to regulate the melting point of the salt bath,
increase the fluidity of the salt bath, and thus enhance
the heat transfer process.

共渗温度820~840℃，共渗时间视锉刀规格大小及具体要求而定，
长250mm的锉刀加热20~ 30min可得到0.4~0.5mm厚的渗层；渗后直
接淬水，低温回火。按上述热处理工艺制造的锉刀的切削性能和
力学性能超过T12A钢制造的同规格的锉刀。从金相分析可见，渗
层最高碳质量分数达0. 8%~0.9%，大量的极细颗粒的碳氮化合物
弥散分布在细针马氏体及残留奥氏体之间，形成了高硬度和高疲
劳强度的表面硬化层。

The infiltration temperature is 820 ~ 840 C, the
infiltration time depends on the size of the file and the
specific requirements. The infiltration layer of 0.4 ~
0.5mm thickness can be obtained by heating the 250mm file
for 20 ~ 30 minutes, and quenching water directly after
infiltration and tempering at low temperature. The
cutting performance and mechanical properties of the
files manufactured according to the above heat treatment
process exceed those of the same specification
manufactured by T12A steel. The metallographic analysis
shows that the highest carbon content of the carburized
layer is 0.8%~0.9%. A large number of ultra-fine
particles of carbonitrides are dispersed between fine-
needle martensite and retained austenite, forming a
surface hardening layer with high hardness and high
fatigue strength.

2)低碳钢锉刀的性能。锉刀是一种不可重磨的刀具。所以就重磨
性而言，它是一种一次性使用的刀具，这就要求它有足够的切削
性能、排屑性能、耐磨性能，以及抗疲劳性能。

2) the performance of low carbon steel files. A file is a
non regrinding tool. So in terms of regrindability, it is
a disposable tool, which requires it to have sufficient
cutting performance, chip removal performance, wear
resistance, and fatigue resistance.

显然，切削性能、耐磨性能与它的齿面硬度关系极大。图3-3给出
了20钢锉刀经上述工艺碳氮共渗后，预冷一直接淬火后得到的齿
面硬度（用超声波硬度计检测）与处理时间关系曲线。从图可
知，仅浸液15~ 30min，齿面硬度即可达到钢锉所需求的最佳硬度
范围63~ 65HRC。

Obviously, cutting performance and wear resistance have
great relationship with its hardness. Fig. 3-3 shows the
relationship between tooth surface hardness (measured by
ultrasonic hardness meter) and treatment time of 20 steel
file after carbonitriding and quenching. It can be seen
from the diagram that the hardness of tooth surface can
reach the optimum range of 63 ~ 65HRC required by steel
file only after 15 ~ 30min of immersion.

锉刀的切削性能与切削齿的齿形有极大关系，由于T12A钢的原始
硬度较高，所以用剁刀片剁齿时齿深很难加工到很深，而用低碳
钢可使齿深增加13.3%，从而改善了切削性能。

The cutting performance of the file is closely related to
the tooth profile of the cutting teeth. Because of the
high original hardness of T12A steel, it is difficult to
cut the teeth very deep with a razor blade. The cutting
performance can be improved by increasing the tooth depth
by 13.3% with low carbon steel.

共渗时间同硬度的关系

Relationship between CO diffusion time and hardness

图3-3 共渗时间同硬度的关系

Fig. 3-3 relationship between infiltration time and
hardness

表3-3给出了20钢经该工艺碳氮共渗30min所制造出来的锉刀部分
性能和目前用的T12A钢锉刀的部分性能对比情况，并列出了世界
名牌锉刀DOUBLE FILES和前苏联标准( FOCT)的主要性能。从这些
对比数据可以发现，用低碳钢制的锉刀，质量很高，以致超过了
世界名牌产品。人们从实践中认识到，锉刀的众多质量指标，综
合反映在两点：一是万次锉削试验中的锉屑克数，二是客户的信
息反馈，用户满意就是高质量的体现。

Table 3-3 gives a comparison of the partial properties of
the file made of 20 steel by carbonitriding for 30
minutes with those of T12A steel, and lists the main
properties of the world famous file DOUBLE FILES and
Former Soviet Union Standard (FOCT). From these
comparative data, it can be found that the quality of the
file made of low carbon steel is so high that it exceeds
the world famous brand products. It is realized from
practice that many quality indexes of file are reflected
in two aspects: the number of filing grains in ten
thousand filing experiments, and the feedback of
customers"information. Customer satisfaction is the
embodiment of high quality.

表3-3 250mm粗扳锉刀锉切性能比较

Table 3-3 comparison of file performance of 250mm rough
wrench file

250mm粗扳锉刀锉切性能比较

Comparison of file performance of 250mm rough wrench file

采用的试块硬度为170~187HBW，截面尺寸为10mm×25mm，压重为
12. 5kg的标准锉削试验规范。从实测数据可见，低碳钢碳氮共渗
锉刀，其万次锉削锉屑克数不仅比原来的T12A钢锉刀提高近
100%，而且超过了名牌DOUB-LE FILES锉刀28%，也超过了前苏联
标准。

The hardness of the specimen is 170-187 HBW, the
sectional dimension is 10 mm *25 mm, and the pressure is
12.5 kg. From the measured data, it can be seen that the
number of cuttings per 10000 times of low carbon steel
carbonitriding file is not only 100% higher than the
original T12A steel file, but also 28% higher than the
famous DOUB-LE FILES file and the former Soviet Union
standard.

3)结论。

3) conclusion.

①采用低碳钢碳氮共渗工艺制作锉刀较原T12A钢盐浴淬火，仅材
料费一项就可降低总成本25%左右，经济效益是可观的。

(1) Compared with the salt bath quenching of T12A steel,
the total cost of the file made by carbonitriding process
of low carbon steel can be reduced by about 25% with only
one item of material cost. The economic benefit is
considerable.

②低碳钢锉刀，大大简化了锉刀的制造工艺，又可以使总成本下
降15%。

(2) the low carbon steel file greatly simplifies the
manufacturing process of the file and reduces the total
cost by 15%.

③新工艺将大幅度提高产品的质量和成品率，使一级品率由目前
的70%提高到90%，从根本上消除了变形开裂，由此而可使总成本
下降15%左右，从而使企业经济效益大大提高。

(3) The new process will greatly improve the quality of
the products and the yield of finished products, so that
the rate of first-grade products will be increased from
70% to 90%, and the deformation cracking will be
eliminated fundamentally. Thus the total cost will be
reduced by about 15%, thus greatly improving the economic
benefits of enterprises.