T12A钢锉刀热处理工艺是什么样的？-钢锉|锉刀-无锡市苏锋工具有限公司

锉刀是一种多刃的切削工具，主要用于锉削硬度在18~58HRC范围
内的金属材料，工作中常受到弯曲变形和冲击，因此要求锉刀在
保证高耐磨性的同时还应具有一定的韧性。我国的锉刀有相当数
量进入国际市场，由于质量不甚优良，其价格仅为国际名牌——
美国双刀牌锉刀的1/8~1/5。尽管两者所用材料化学成分相近，但
失效形式完全不同。双刀牌锉刀主要为正常磨损失效，国产锉刀
则主要为断齿崩刃等非正常失效，寿命差距很大。为提高国产锉
刀质量，首先对进口高寿命锉刀进行分析解剖，进而针对性地提
出整改措施。
File is a multi-edged cutting tool, mainly used for
filing hardness in the range of 18 ~ 58HRC metal
materials, work is often subject to bending deformation
and impact, so the requirements of the file in order to
ensure high wear resistance at the same time should have
a certain degree of toughness. A considerable number of
Chinese filings have entered the international market.
Because of their poor quality, their prices are only one-
eighth to one-fifth of those of the international famous
brand, the American double-blade file. Although the
chemical composition of the two materials is similar,
their failure modes are completely different. The double-
blade file is mainly normal wear failure, while the
domestic file is mainly abnormal failure, such as broken
teeth and broken edges, and the life gap is very big. In
order to improve the quality of domestic file, firstly,
the imported high-life file is analyzed and dissected,
and then the rectification measures are put forward.
1)双刀牌锉刀的质量分析。
1) quality analysis of double tool file.
①化学成分。由表3-8可知，双刀锉刀与国产锉刀的化学成分相
近，所用材料相当于国产T12A，不过微量元素有些差异。
(1) chemical constituents. As can be seen from Table 3-8,
the chemical composition of the double-blade file is
similar to that of the domestic file, and the material
used is equivalent to that of the domestic T12A, but
there are some differences in trace elements.
表3-8 锉刀用钢化学成分（质量分数） (%)
Table 3-8 chemical composition (mass fraction) of file
steel (%)
锉刀用钢化学成分（质量分数）
Chemical composition (mass fraction) of steel for file
②锉削试验。用8in细扁锉作试验，双刀牌锉刀的锉削达到一定次
数后，锉削曲线呈平缓状，表明该锉刀持久性好，使用寿命长，
在达到50万次时锉齿表面仍保持良好的锋利的状态。相反，国产
锉刀锉削一般在达到30万次以后，断齿崩刃的现象就大量出现，
不能继续使用。
Filing test. The experiment with 8-minute thin flat file
shows that the curve of the double-blade file is smooth
after cutting for a certain number of times. It shows
that the file has good durability and long service life,
and the surface of the file teeth remains in a sharp
state when it reaches 500,000 times. On the contrary,
after 300,000 times of domestic filing, a large number of
broken teeth and broken edges appear and can not be
continued to use.
③组织形态及断口形貌。在双刀牌锉刀的显微组织中发现，碳化
颗粒大小不均，相当数量的大颗粒碳化物均匀分布在组织中，且
碳化物颗粒棱角钝化。在透射电镜下观察，基体组织为隐晶马氏
体，其中有大量的板条马氏体。国产锉刀的显微组织是片状马氏
体和弥散的碳化物小颗粒。
(3) histomorphology and fracture morphology. In the
microstructure of the double-blade file, it was found
that the size of carbide particles was uneven, a
considerable number of large particles of carbide were
uniformly distributed in the microstructure, and the
edges and corners of carbide particles were passivated.
Under transmission electron microscope, the matrix
structure is cryptocrystalline martensite, and there are
many lath martensite. The microstructure of domestic
files is lamellar martensite and dispersed carbide
particles.
④质量分析。双刀牌锉刀和国产锉刀用材的化学成分相近，仅仅
是组织结构的差异，即碳化物形状与基体组织的形态不同。双刀
牌锉刀所获得的这种特殊组织结构，正是其质量好的主要原因。
T12A钢是过共析高碳钢，脆性较大。常规的热处理都是以获得细
小弥散的碳化物为目标，改善其韧性以得到强韧化效果。然而对
这种特殊工作条件下工作的工件，耐磨性是第一位的，要得到良
好的锉削性能，在组织中保持一定数量的大颗粒碳化物是很有效
的方法。只是这样势必会使本来就很脆的材料的韧性进一步下
降。因此，还必须通过热处理来获得韧性极好的板条马氏体并将
碳化物颗粒的棱角钝化。
(4) quality analysis. The chemical composition of the
double-blade file is similar to that of the domestic
file, but the difference of the structure is only the
difference of the carbide shape and the matrix structure.
The special structure of the double knives file is the
main reason for its good quality. T12A steel is
hypereutectoid high carbon steel with high brittleness.
Conventional heat treatment aims to obtain fine dispersed
carbides and improve their toughness in order to obtain
strength and toughness. However, the abrasion resistance
of the workpiece under this special working condition is
the first. To obtain good filing performance, it is an
effective method to keep a certain amount of large
particles of carbide in the structure. Only in this way
will the toughness of the material which is already
fragile become lower. Therefore, the lath martensite with
excellent toughness must be obtained by heat treatment
and the edges and corners of carbide particles must be
passivated.
由上述分析可知，如果采用某种特殊的热处理方法，获得与双刀
牌锉刀相近似的显微组织结构，必将使国产锉刀的使用寿命大大
提高。
It can be seen from the above analysis that if a special
heat treatment method is adopted to obtain the
microstructure similar to that of the double-blade file,
the service life of the domestic file will be greatly
improved.
2)锉刀热处理工艺。
2) file heat treatment process.
①预处理工艺。为了达到上述强韧化的效果，采用了如图3-5所示
的两段等温球化退火工艺，改变了锉刀的原始组织状态。首先把
钢加热至比Accm(820℃)稍高的840~850℃的高温，适当保温，使
组织中只保留为数不多的碳化物颗粒，且奥氏体组织不均匀。然
后进入第一阶段——球化退火阶段，在Ac1( 730℃)以上的等温阶
段较短，不均匀奥氏体中未溶碳化物和高浓度碳偏聚区都将成为
大颗粒碳化物萌生长大的核心。同时在周边组织中碳浓度降低，
为淬火后得到板条马氏体做好组织准备。当进入第二阶段球化退
火时，即在Ac1以下等温，碳化物进一步扩散、析出、聚集球化，
使得大颗粒碳化物进一步球化长大，并新生许多弥散分布的小颗
粒碳化物。这样就形成了一定数量的大颗粒碳化物及大量低碳的
基体组织。这种先期的组织为最终热处理创造了良好的组织条
件。
(1) pretreatment process. In order to achieve the above
strengthening and toughening effect, the two-stage
isothermal spheroidizing annealing process as shown in
Fig. 3-5 was adopted to change the original
microstructure of the file. Firstly, the steel was heated
to 840 ~ 850 C higher than that of Accm (820 C), so that
only a few carbide particles were retained in the
microstructure and the austenite structure was
inhomogeneous. Then the first stage, spheroidizing
annealing stage, is shorter than the isothermal stage
above Ac1 (730 C). Undissolved carbide and high
concentration carbon segregation zone in inhomogeneous
austenite will become the core of large carbide sprouting
and growth. At the same time, the carbon concentration in
the surrounding tissues is reduced, so as to prepare the
lath martensite after quenching. When entering the second
stage of spheroidizing annealing, i.e. below Ac1, the
carbide further diffuses, precipitates, aggregates and
spheroidizes, resulting in further spheroidizing and
growth of large particles of carbide, and the formation
of many small particles of dispersed carbide. This
resulted in the formation of a large number of large
granular carbides and a large number of low carbon matrix
structures. This pre organization creates a good
organizational condition for final heat treatment.
T12A钢两段球化退火工艺
Two stage spheroidizing annealing process of T12A steel
图3-5 T12A钢两段球化退火工艺
Fig. 3-5 two stage spheroidizing annealing process for
T12A steel
②最终热处理工艺。采用快速加热短时保温的热处理工艺。由于
加热温度较低，保温时间短，碳化物颗粒大小不均，溶解速度不
同，故得到成分极不均匀的奥氏体和一定数量的碳化物。淬火后
组织结构与美国双刀牌锉刀相近，为一定数量的板条马氏体和较
多的隐晶马氏体，碳化物大小不均，且棱角钝化。
(2) the final heat treatment process. Heat treatment
process with quick heating and short time insulation is
adopted. Because the heating temperature is low, holding
time is short, carbide particle size is uneven,
dissolution rate is different, so a very uneven
composition of austenite and a certain number of
carbides. The microstructure after quenching is similar
to that of American double-blade file. It is lath
martensite and more cryptocrystalline martensite. The
size of carbide is uneven and the edges and corners are
passivated.
国产T12A钢锉刀按上述工艺处理后，断口形貌与双刀牌锉刀相
似，出现了大量的浅口韧窝和撕裂棱，而传统工艺处理的锉刀断
口形貌基本为准解理和沿晶型。锉削试验都能达到50万次以上，
达到双刀牌锉刀水平，失效形式为正常磨损失效，基本消除断
齿、崩刃等非正常失效现象。
The fracture morphology of T12A steel file made in China
is similar to that of double-blade file. A large number
of shallow dimples and tearing edges appear. However, the
fracture morphology of T12A steel file treated by
traditional process is quasi-cleavage and intergranular.
Filing test can reach more than 500,000 times, reaching
the level of double-blade file, the failure form is
normal wear failure, basically eliminating abnormal
failure such as tooth breakage, edge breakage and so on.